When to tap maple trees in Wisconsin

Maple season in Wisconsin usually opens mid-March and winds down early April. Here's the long-run pattern, the year-by-year record, and what the forecast says right now.

Typical season
Opens
March 15
Closes
April 9
Recent openings ranged
Mar 4 – Mar 28 (2011–2022)
Typical length
About 28 days
Sap-flow outlook right now

Forecast for Wausau

Updated Sep 26, 8:06 AM EDT

It's the off-season. Sap needs freezing nights, and there are none in sight. Wisconsin's season usually opens around March 15 — 170 days from now.

No freeze-thaw days in the forecast

Blue = below 32°F · Amber = thaw · dashed line = freezing

  1. SunSep 27
    67°high
    45°low
    0h frozen
    24h thawed
    No freeze, no run
  2. MonSep 28
    73°high
    53°low
    0h frozen
    24h thawed
    No freeze, no run
  3. TueSep 29
    70°high
    50°low
    0h frozen
    24h thawed
    No freeze, no run
  4. WedSep 30
    68°high
    56°low
    0h frozen
    24h thawed
    No freeze, no run
  5. ThuOct 1
    67°high
    54°low
    0h frozen
    24h thawed
    No freeze, no run
  6. FriOct 2
    66°high
    46°low
    0h frozen
    19h thawed
    No freeze, no run

Data: National Weather Service. Verdicts use freeze-thaw thresholds from maple field research; your woods may run a little differently.

Full Wisconsin sap forecast →
Wisconsin seasons, 2011–2022
JanFebMarAprMaymedian start Mar 1520112011: Mar 15 – Apr 1220122012: Mar 8 – Mar 1820132013: Mar 25 – Apr 2320142014: Mar 28 – Apr 1920152015: Mar 14 – Apr 620162016: Mar 6 – Apr 420172017: Mar 4 – Apr 220182018: Mar 16 – Apr 2120192019: Mar 21 – Apr 1420202020: Mar 7 – Apr 420212021: Mar 6 – Mar 3120222022: Mar 18 – Apr 20
Each bar is one season, from the approximate average opening date to closing date reported by USDA NASS.
How to know it's time

Sap runs on a temperature swing, not a date. A night below freezing loads the tree; a day above freezing pushes sap out of the taphole. Field research treats a low under about 30°F followed by a high over about 37°F as a real freeze-thaw day, and big runs almost always come on days like that.

So watch the 10-day forecast. When you see a string of nights in the 20s and afternoons in the 40s, get your taps in a day or two ahead. Tap south-facing slopes first — they warm and run earlier.

Dates are USDA NASS approximate state averages. Wisconsin has the latest median opening date of the NASS states.

Seasons are shifting. In New England and New York, the sugaring season now begins about 8 days earlier and ends about 11 days earlier than it did 40 years earlier, leaving it roughly 3 days (about 10%) shorter, according to UVM Proctor Maple Research Center survey records analyzed in 2007.

Plan your season

Sources

  1. USDA NASS — Maple Syrup Production — news release, June 2013 (average open/close dates 2011–2013) — USDA National Agricultural Statistics Service (mirrored by the University of Vermont)
  2. USDA NASS — Maple Syrup Production — news release, June 2014 (average open/close dates 2012–2014) — USDA National Agricultural Statistics Service (mirrored by the University of Vermont)
  3. USDA NASS — United States Maple Syrup Production, June 11, 2015 (average open/close dates 2013–2015) — USDA National Agricultural Statistics Service (mirrored by the University of Vermont)
  4. USDA NASS — United States Maple Syrup Production, June 15, 2016 (average open/close dates 2014–2016) — USDA National Agricultural Statistics Service (mirrored by the University of Vermont)
  5. USDA NASS — United States Maple Syrup Production, June 14, 2017 (average open/close dates 2015–2017) — USDA National Agricultural Statistics Service (mirrored by the University of Vermont)
  6. USDA NASS — United States Maple Syrup Production, June 13, 2018 (average open/close dates 2016–2018) — USDA National Agricultural Statistics Service (mirrored by the University of Vermont)
  7. USDA NASS — United States Maple Syrup Production, June 12, 2019 (average open/close dates 2017–2019) — USDA National Agricultural Statistics Service (mirrored by the University of Vermont)
  8. USDA NASS — Crop Production, June 2020 — maple syrup tables (average open/close dates 2018–2020) — USDA National Agricultural Statistics Service (mirrored by the University of Vermont)
  9. USDA NASS — Crop Production, June 2021 — maple syrup tables (average open/close dates 2019–2021) — USDA National Agricultural Statistics Service (mirrored by the University of Vermont)
  10. USDA NASS — Crop Production, June 2022 — maple syrup tables (average open/close dates 2020–2022) — USDA National Agricultural Statistics Service (mirrored by the University of Vermont)
  11. USDA NASS — Crop Production, June 2023 — maple syrup tables (average open/close dates 2021–2022; discontinued 2023) — USDA National Agricultural Statistics Service (mirrored by the University of Vermont)
  12. USDA 2022 Census of Agriculture, County Data — Table 37. Maple Syrup: 2022 and 2017 (Wisconsin) — USDA National Agricultural Statistics Service
  13. Statement of Timothy D. Perkins, Ph.D., Director, UVM Proctor Maple Research Center — Global Warming Mountaintop 'Summit': Economic Impacts on New England (June 4, 2007) — U.S. House Select Committee on Energy Independence and Global Warming

Common questions

When is maple syrup season in Wisconsin?
Usually from mid-March to early April — about 4 weeks. The exact start moves by weeks from year to year with the weather.
When should I tap my trees in Wisconsin?
Tap just before the first good run: when the forecast shows nights below freezing and days climbing to around 40°F. In a typical year that's around March 15. Tapholes dry up within 6 to 10 weeks, so tapping far too early can cost you the late runs.
What weather makes sap run?
Freezing nights and thawing days. Field research counts a freeze-thaw day as a low under about 30°F and a high over about 37°F; nights in the 20s and days in the 40s are the classic sap days.
Other states
ConnecticutIllinoisIndianaIowaKentuckyMaineMassachusettsMichiganMinnesotaMissouriNew HampshireNew YorkOhioPennsylvaniaVermontWest Virginia

Get a heads-up when Wisconsin's sap will run

LuckySap checks the forecast for your trees and can ping you the night before a strong sap day — then keeps every collection and boil in one season log. Free on iPhone.

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