2021 Maple Syrup Season in Pennsylvania

Hey there. Nice to meet you. I started this post in January 2021, as a journal-style article as I got ready for the (at that time) upcoming 2021 Maple Syrup Season. If you want to find out what’s happening in 2022 you may want to jump over to that article here.

Throughout the season, I updated this article with the actual amounts of sap that I collected from the silver maple tree in my yard, in the Philadelphia suburbs.

After the season was completely over, I edited and summarized here to create this overview of the 2021 Maple Syrup Season in Pennsylvania. I started this website in 2019, to document my foray into this new, sweet hobby. I grew up as a city-kid, in Northeast Philadelphia, so it never really occurred to me that you could make your own maple syrup from the ‘regular’ maple trees in your yard.

Making maple syrup from maple sap collected with a tap kit is relatively easy to do, but the hardest part is figuring out when to tap your trees. When I started out, the only information available was some vague notions about the right time of year when temperatures are routinely above freezing during the day and below freezing at night.

That’s actually good advice, but not really specific enough to be very helpful. When, exactly, is that? Given the fact that the season is only about 6 to 8 weeks long, being wrong by a few weeks can put a serious dent in how much sap you will actually collect.

My goal with this article and the one I started in 2019, is to share the details with you, so that you can use this information to decide for yourself when the best time to tap trees is. Your weather won’t be the same as mine here, but perhaps you can make a few adjustments based on your own climate to triangulate on a successful time to start.

two people tapping a maple tree using a drill
Figuring out when the best time to tap the trees is maddening

Executive summary: how was the 2021 maple syrup season?

I’m not going to maple sugar coat this…the 2021 maple syrup season was almost a complete bust for me. Due to COVID-related cabin fever, my expectations were super high. But my timing was completely off. I tapped my tree on Valentine’s day (Feb 14), but the result was that the season was very short. The yields were low.

I don’t want that to happen to me again, and I don’t want it to happen to you, either, if you can help prevent it.

After the season was over, I collected weather data from Penn State, to add to my own personally collected data, in order to help diagnose exactly what happened and what I should have done differently.

This first chart will be a bit hard to read, but what I did was color code every day where the low temperature of the day was 30 degrees Fahrenheit in lime green. I then color coded every day when the high temperature was 36 degrees Fahrenheit or above in dark green. Then, whenever I had 2 greens in the same day, I flipped the color for both to yellow, signifying peak sap flow conditions.

detailed weather data 2021

Then, I went back through and counted how many peak sap flow days were in each 6-week period of time, based on different starting dates, going all the way back to January 1st.

Here is what I found:

Peak flow days in a 6 week period

With the gift of hindsight and a handy chart here, you can plainly see that this was a relatively ‘early’ season. The top weeks to start were either January 7th or February 2nd.

But remember, one of the key assumptions here was limiting the analysis to a 6-week period of time. We know that, with some luck and great weather, we can sometimes have an 8-week season.

So I went back to each of those starting points and I added 2 more weeks. You can see the data in the next chart:

peak flow days over 8 week periods 2021

This next view tells a quite compelling story that maple syrup season, most certainly, started at the beginning of January. The theoretical peak time to tap was January 7th. It was already tied for 1st place in the 6-week analysis, and with the benefit of 2 extra weeks of potential upside, it seals the deal.

The distribution of this weather data also highlights what a poor choice it was to tap later in February. Those dates were worse in terms of the 6-week data, and they had essentially zero-upside of a 2-week extension.

That means the Maple syrup harvesting season in 2021 was the 6 to 8 week period starting January 7th.

What to do differently in the 2022 Maple Syrup Season?

In 2022, the plan is definitely to tap earlier…like beginning of January. I’m going to watch the weather closely, and if it looks like the weather is going to be in the sweet spot (pun intended), I’m going for it. The analysis above gives me great confidence there. Sure, I could get frozen out early, but there are so many advantages to being early, compared with being late.

The early sap is the clearest, purest, and premium. And taps dry up when they clog up with bacterial growth–and the risk of bacterial growth goes up with the temperature.

I also learned a lot about which side is the best to tap and shared it here.

When was the best time to tap a maple tree in Pennsylvania?

According to an analysis of 2021 weather data from Allentown, PA, the best time to tap a Maple tree in 2021 was January 7th. Both the  6-week and 8-week periods following January 7th had the most days with ideal temperatures (Lows of 30 and below with  Highs 36 and above).

The best time to tap a Maple Tree for sap

The ideal weather to tap a tree and start making Maple syrup is when it dips well below freezing overnight and then up into the 40s during the day.

When the temperature drops below freezing, the sap that is stored in the roots of the Maple trees also freezes up, causing crystals to form. If you’ve ever frozen a beverage in your freezer, you’ll know that frozen water takes up more space and expands.

Then, when the temperature warms up, the sap warms up too, thaws out, and then runs up the tree, which is why we call it a sap run.

All the traditional advice is that you want to wait for that weather pattern to tap your tree–and to expect sap to be collected for about 6-8 weeks after that. The part that has frustrated me, however, is that absent a crystal ball, there is no real way to predict what the weather holds and there are plenty of traps. For example, check out the local weather coming up.

Can you tap maple trees too early?

Yes, you can tap maple trees too early. Your entire season will be about 6-10 weeks long. The best time to tap them is when you expect the temperature to be in the 20s (Fahrenheit) at night and high-30s to mid-40s during the day, for the majority of days.

The sap will flow freely, and in large volumes, on those textbook days that meet those temperature thresholds, and flow will be stingy or downright nonexistent on those other days. As you can imagine, the trick, therefore, is to predict the day when you can expect the most ‘in the zone’ days over the subsequent 6-10 weeks.

If you tap maple trees too early, you will end up with much less sap volume than if you tap at the right time. If you tap too late, your sap will be of lower quality and also potentially lower volume.

Find out how much sap you can expect to harvest here.

What I learned comparing 2019 to 2021

Picking the optimal time is challenging and also involves some luck.

In 2019, I started on January 19, when the temperature looked right on paper for 3 of 7 days. But two of those days were surrounded by bitter cold, and the sap didn’t really flow until the third week when the sap yield took off.

This is the weather report in my area over the next week. I’m starting this investigation two full weeks earlier than in 2019, but it is driving me crazy, because, from the looks of it, it is perfect Maple syrup making time, right now.

2021 Weather and Maple Sap Collecting journal

One last thing before we get started–I’m writing this article somewhat journal-style, meaning that I’ll come back to it every few days (or a week when sap running is slow or life is too hectic) to report back.

Hopefully, that means updates for you–but that also probably means the present, past and future tense of my writing will be a bit jumbled until I get to edit the piece at the end of the year. I appreciate your patience there and hope it isn’t maddening.

January 2, 2021- January 9, 2021

January 2 - 9 2021
I missed it, this would have been an amazing week for sap

Hard to believe, but it looked like the beginning of the 2021 Maple Syrup Season in Pennsylvania started in the first week of January.

It felt way too early, and I had not tapped my trees yet, but the weather was nearly perfect every day.

If I had tapped my trees, there is no doubt that some of the highest quality sap would have been flowing. But this early in the season, deep freezes can still set in and shut everything down.

Since we only have a precious few weeks to collect sap, we want to identify that time when we will get the best string of days for collecting over a 4-6-week period.

Due to my own predictions that it would get significantly colder again before it got warmer, I sat that week out, hoping for a long season that extended into the early Spring.

January 11, 2021- January 18, 2021

January 11, 2021 weather
This was the second week in a row for perfect maple syrup weather

The second week of the year was another perfect week for the 2021 Maple Syrup Season in Pennsylvania.

Take a look at the weather above and see for yourself.

I have to admit that watching a weather report like that and not tapping is a maddening event.

The weather has been in a perfect range–but what kept me out was a lingering doubt that the weather couldn’t/wouldn’t hold up.

Based on the forecast, these days look exactly like my prime sugaring days in 2019. That year, my best days were during swings from the coldest temperature of ~20-25 Fahrenheit to the warmest temperature of at least 39, upwards of 50 degrees.

Ugh! It is excruciating to sit on the sidelines and report-out without tasting that sugar. I need more trees!

The buds started to form on the branches. There was most certainly sap flowing in that tree.

Towards the end of the week, the weather report in the news started to shift to something called a polar vortex. I’m not really sure what that is and not sure I really care other than I hear a tiny voice in my head reassuring me that I was right to wait and not start the season too early.

Time will tell.

The plan at this time was to hold off at least another week, before I officially opened up the 2021 Maple Syrup Season in Pennsylvania at the Ulrich Sugar Shack…and by that I mean 2 maple trees in my suburban yard).

In the meantime, I started to get my gear ready. Do you have your gear ready? Check out this post for the best Maple tree tap kit.

January 18- January 25, 2021

Here is what the weather looked like for the third week in January, 2021:

Weekly weather forecast starting January 18th
Several days this week would have produced nice sap yields

It definitely got a little colder, but 4-5 days that week would have been solid, and the other days were cold enough that they would have helped build up the pressure to add to the following days.

At this point in the season, I was starting to think I had messed up and waited too long. Who would have figured January was the best month for sap. Only time will tell.

Still waiting…

Sounds counterintuitive, but I’m hoping for a cold blast to shut things down for 1-2 more weeks and a fresh/clear time to start right after.

January 24- January 31, 2021 Weather

Here is the 7-day weather forecast for Sunday to Sunday, the last week in January.

Jan 24 to 31st weather
A cold snap like this will shut down the maple sap run. Monday and Wednesday would have likely produced sap, but the other days were too cold. If we get a few weeks of this it could shut things down

You can see from the hourly forecast (that wavy yellow line at the top) that Sunday night into Monday was still maple sap weather,  but then the temperature dropped.

That’s the cold snap I was anticipating. You can see that between the high and low temperatures there was some freezing and thawing, but perhaps not the spread needed to really get the sap flowing.

This weather pattern snapped me out of my malaise. I was just waiting for the weather to cooperate, so I could get out there and tap-away.

January 31 to February 7

That cold front did come through last week–it was not a great week for tapping maple trees. At this point, we are through January (almost). It is possible that Thursday, February 4th will start the Maple Syrup season for me here.

Check out the 7-day weather forecast:

is the weather ready to tap a maple tree?
Based on this weather forecast, Thursday-Saturday could be okay days for collecting sap. The other days are likely too cold

The temperature is too cold Sun- Wednesday, but Thursday, Friday, and Saturday all have great temperature ranges.

Given the fact that we are in the midst of a cold snap, progressing into February with what looks like some warmer temperatures at the end of the week, I’m going to try and watch the weather closely and may get out there on Thursday.

Fingers crossed.

Here is how the week turned out–we got a lot of snow–like two feet of snow. There were at least 2 decent days for maple tree tapping, but based on the weather forecast, I resisted the urge.

Rather than start warming up, we actually are experiencing a cold snap next week. Check it out.

February 9 – 16

As expected, it is cold. very cold. The forecast looked too cold this week to tap my tree.

But, as the week progressed, the weather outlook improved:

As of 2/14 (Happy Valentines Day), here is the 7-day forecast:

Based on that weather, it looks like Sunday might be an okay day–Tuesday, Friday, and the following Sunday should all be great. Looking ahead at a 10-day forecast, the following Monday and Tuesday look great too!

So I tapped my tree on February 14, 2021. Tuesday was a perfect day for collecting sap.

sap leaking from behind a maple tree tap

But I did notice that my tap hole was leaking sap. There are two major reasons this happens–either the hole I drilled was wobbly and irregular, and too large for the tap, or the tap was not inserted all the way.

Luckily for me, all I had to do was push the tap in further with a hammer and I was all set.

Despite losing some volume to the ground from my leak…it was a great collection.

Textbook day and the yield proved it.

More than a gallon of sap in one day!

By the way, after boiling down the gallon of sap to a concentrated pint, the kitchen room was filled with humidity. This is the wall of my kitchen above the cabinets…literally dripping with evaporated water :).

That’s why everyone recommends you do the bulk of evaporation outside. But where’s the fun in that?

But then the weather turned colder. Neither Friday nor Sunday ended up being great days for sap.

February 21- 28

Here is the weather forecast for this coming week:

I really wish Sunday 21st was 2-3 degrees warmer…but from the looks of it, should get a stretch of good days ahead, as long as the nights get cold enough.

February 23 and 24th were very good sap-collection days. 2756 g on the 23rd and 4124 on the 24th!

March 1-5

Sorry, I messed up and didn’t take a screenshot of the weather this week. Here’s a different view of the temperature range that I was able to find.

Let me tell you that it was Sooo close to perfect weather…but in reality, it wasn’t.

March 3rd was a pretty good day. 3,347 g of sap (approximately 3.3 L). March 4th was nearly perfect, but it only got down to 32 degrees F before hitting the 40s…and yielded pretty much zero sap.

The rest of the week was either too hot or too cold. Goldilocks would have been bummed.

There was rain during the week as well. One day there was about 600g of sap, but it was tinged yellow/brown. Take a look:

yellow sap
That is not concentrated syrup, that is yellow sap

You end up with yellow sap when rainwater drips down the tree trunk and into your sap bucket.

Technically, it’s still good to use.

March 6 – 13

Here is what the weather had in store for the week of March 6-13.

Friday into Saturday never got cold enough. Since I had about 2.5 gallons saved up, I decided to make maple candy today. You can read more about that here.


Sunday and Monday seemed pretty close to textbook days, and both yielded sap, but not as much as I had thought or hoped.

Sunday yielded 1301 grams and Monday was 811 grams, which ends up being around 1/2 gallon, combined. Which feels really low, despite nearly perfect weather.

I actually think my taps may be drying up. I looked back and this is the same week the run shut down in 2019.

Buds did break on the tree. Fingers crossed for some more cool weather soon. Hah, did I really just type that?

March 14-21

The weather was mixed this week, much of it too cold for making Maple syrup. Earlier in the week, I checked the bucket and was skunked. Towards the end of the week, I collected 1616 g on Saturday (from Thur-Fri) as the first and only harvest.

The only problem is that it rained a lot and the sap in the bucket had a gross, brown appearance and taste.

Then on Sunday, I harvested a clear, clear, and very sweet 612g on Sunday.

March 22-29

While it looked like Monday would have been a good day for sap, it wasn’t. There was a lot of rain and a lot of rainwater in my bucket. Calling that whole week a zero yield week.

March 30-April 6

When I looked at the week ahead, I was a bit conflicted–after a long winter, the allure of transitioning quickly to a warm Spring seemed too great to resist–but at the same time, I was hoping for a bit more cold evenings to drive up the sap.

Before the week started, I predicted that Thursday and Friday may have been my last two days of the year.

Turned out, I yielded zero sap each of those two days. The only thing I collected was a bunch of rainwater on Wednesday.

Looking at the weather ahead of me–it looks like it will be too warm. Hope it’s a bit cooler where you are and that your lines are running!.

April 5 – 12


      1. Hey there and howdy neighbor!
        I am located about 40 miles just northeast of you – and this is my first maple tap attempt ever!
        I just installed my very first tap, on Friday Feb 19, 2021. It dripped right away, but leaked from just under my spile and dripped down the tree trunk but not into my bucket. So after trying several things, tapping in further, etc it still leaked around the outside of the spile..so…i removed it and moved it to another spot yesterday on Feb 22 Monday. I also added another tap to a nearby maple and ran two hoses into a covered 2 1/2 gallon collector bucket. The low last night was near freezing but not below. I checked it today at dusk, and saw a little sap in the lines and had about one ounce only in the bucket at dark today. So…we’ll see!
        Can i really get as much as two gallons a day?
        wow -I’d better check it daily, if so.
        Keep us updated!
        and Good luck!
        Jersey Jim

        1. Jersey Jim! Neighbor! Great to meet you virtually. Thanks for the comment and congratulations on starting. I, too, had some dripping coming out of my taps this year. My issue was able to be fixed by tapping (pun intended) it in deeper/more flush with the mallet. I was fortunate that my own issue was just that it wasn’t flush.

          So far, this season, I have two taps in my large maple and I get about 0.75-1 gallon in total (sometimes a bit more, sometimes a bit less) on a good day. Seems like yields are much lower. I have two trees–one fairly large (as mentioned) the other tappable, but in 2019 (the last year I tried), it didn’t yield much sap at all…so I just left it alone this year.

          Sharing that to set expectations a bit. In 2019, I was getting much bigger bucketfuls. But the reason I took off last year is that my trees took significant damage during a storm. I think my tree may still be recovering.

          With that said, the size of your trees and the weather will determine how much you get. I wish you amazing success and hope you get more than 2 gallons a day (you may need another bucket 🙂 ) But right now, I’m averaging 3/4 to 1 gallon or so from two taps combined…if your tree runs like my big one…and of course less if it runs like my slower tree.

          Hope that helps. I will continue to keep you posted, and PLEASE, keep us posted here, too. My whole goal is to help people like you and me who are searching around to figure out what to do and what to expect, so I’d very much welcome the addition of your other real-world experience.

          By the way, I had a solid collection day on March 3rd, did you, as well? The weather has been so close…but not quite good enough. I made maple candy with the sap collected from 2/23-3/3. Yum.

  1. Hello PA tappers! I am in my third-ever season of maple sugaring. I live in Lancaster County (the town of Lititz), so I’m a good bit south of you. I tapped this year on Tuesday, March 16, and have had slow but steady flow except for Saturday & Sunday when I could barely keep up! I have a good size sugar maple and a medium size red maple (which I tapped the first time this year). Saturday I collected about 2 gallons of sap, and Sunday it was almost 3!
    I found this site when I decided to look for local tappers, to chat a bit about some questions coming up. I’d love to discuss the timing of initial tapping (you are so right it is maddening trying to guess the right time to start!), boiling it down to syrup, and how the syrup should look when it’s jarred.
    I just looked at your links, and found very helpful info on filtering & sugar sand. Looks like I need a couple more accessories to round out my collection!

    1. Hi Kate, so nice to meet you! This is so exciting, I didn’t know there were this many of us out there :). Thanks for posting the comment and congratulations on your slow but steady flow. Almost 3 gallons of sap! Yum.

  2. Hello! I’m so glad to hear how another hobby sugar maker is doing this year in PA. I’m up here on the edge of the Poconos and the weather this year has really kept me guessing. I tapped my trees late in February, sap flowed then everything stopped and froze solid for a couple of weeks. Luckily the last few weeks have been great and it looks like I’ll get a couple gallons of lovely syrup. Thanks for the info on why there’s sap down the tree and not in the bucket. It’s actually what I was searching for when I found your page. Enjoy the rest of the season!

    1. Hi Steph,

      Thanks for the comment. Glad to see another tapper here in PA. We were just up your way taking in one of the last snow tubing days on the mountains! Sounds like you’re in good shape, with a couple of gallons. As far as the sap the tree, I am a crash-test-dummy at your service :). Glad you found the site. Hope you have a great rest of the season.

  3. Very nice data collection and analysis on your project! We live in Bedford County, and this will be our 11th season making syrup. Once you start, it’s a hobby that is hard to quit! We call it “catching the bug”.

    2022- Still too early to tap out here as we are experiencing high temps in the teens. A cold winter makes for the best sugaring season though. If you ever find your way out here, I’ll show you some nice sized operations.

    1. Hi Seth,

      Thanks for the comment and compliment. I do appreciate it. Congrats on your 11th season! That’s a great streak. I completely agree with you, once you start, it’s hard to quit. I do wish you lots of luck, out there in Bedford County and I look forward to hearing how your season goes!

      In the meantime, I’ll keep posting here.


Leave a comment

Your email address will not be published. Required fields are marked *