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Wisconsin · county maple atlas

Maple sugaring in Lincoln County, Wisconsin

Lincoln County had 38 maple operations and 52,052 taps in the 2022 Census. Around Merrill, sap usually runs from March 21 to April 15. Here's the long-run pattern, 36 seasons of sap weather, and the outlook this week.
Too early to tapAbout 166 days until the usual start.
Sap starts
Mar 21
typical year
Season ends
Apr 15
about 4 weeks
Sap days / season
37.1
1991–2026 average
Taps, 2022
52,052
#11 of 60 in WI

Sap-flow outlook at Merrill right now

Full Wisconsin forecast →

Forecast for Merrill, WI

Updated Oct 6, 9:36 AM EDT

Off-season for now. Sap needs freezing nights, and none are in sight. Lincoln County's season usually opens around March 21, which is 166 days away.

No freeze-thaw days in the forecast

freeze thaw 32°F

  1. WedOct 7
    46° / 70°

    0h below · 24h above

    No refreeze forecast
  2. ThuOct 8
    40° / 65°

    0h below · 24h above

    No refreeze forecast
  3. FriOct 9
    37° / 67°

    0h below · 24h above

    No refreeze forecast
  4. SatOct 10
    46° / 75°

    0h below · 24h above

    No refreeze forecast
  5. SunOct 11
    57° / 76°

    0h below · 24h above

    No refreeze forecast
  6. MonOct 12
    51° / 64°
    No refreeze forecast

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

When the sap runs

The sugaring calendar at Merrill

Freeze-thaw weather at Merrill peaks in the weeks of Mar 2 to Apr 20, which hold about 66% of a season's sap days. March is the busiest month.
Typical season: Mar 21 – Apr 150246Week of Dec 1: 1.0 sap days on averageWeek of Dec 8: 1.1 sap days on averageWeek of Dec 15: 0.6 sap days on averageWeek of Dec 22: 0.7 sap days on averageWeek of Dec 29: 0.4 sap days on averageWeek of Jan 5: 0.5 sap days on averageWeek of Jan 12: 0.3 sap days on averageWeek of Jan 19: 0.2 sap days on averageWeek of Jan 26: 0.5 sap days on averageWeek of Feb 2: 0.9 sap days on averageWeek of Feb 9: 0.9 sap days on averageWeek of Feb 16: 1.1 sap days on averageWeek of Feb 23: 1.4 sap days on averageWeek of Mar 2: 2.3 sap days on averageWeek of Mar 9: 2.6 sap days on averageWeek of Mar 16: 3.4 sap days on averageWeek of Mar 23: 3.4 sap days on averageWeek of Mar 30: 3.7 sap days on averageWeek of Apr 6: 3.5 sap days on averageWeek of Apr 13: 2.5 sap days on averageWeek of Apr 20: 2.9 sap days on averageWeek of Apr 27: 1.6 sap days on averageWeek of May 4: 0.7 sap days on averageWeek of May 11: 0.6 sap days on averageWeek of May 18: 0.2 sap days on averageWeek of May 25: 0.0 sap days on averageDecJanFebMarAprMaytaps in ~Mar 21
Average number of freeze-thaw sap days in each week of the season at Merrill, 1991–2026. A sap day is an overnight low under 30.2 °F followed by an afternoon high over 37.4 °F. The shaded band is the typical season.

Year-to-year spread

Opening signal
Median Mar 18; the middle half of seasons fell between Mar 10 and Mar 24. Earliest Feb 15 (2012), latest Apr 1 (2013).
Closing signal
Median Apr 18; middle half between Apr 12 and Apr 26. Earliest Mar 15 (2012), latest May 3 (1996).
Sap days by month
Dec10%Jan5%Feb12%Mar35%Apr34%May5%

36 seasons of sap weather

Lincoln County seasons, 1991–2026

The best sap year at Merrill was 2024 with 52 freeze-thaw days; the leanest was 2013 with 26. Seasons that start early tend to end early too: the trees run on the swing between freezing nights and mild days, and heat ends it.
JanFebMarAprMaysap days20262026: Mar 10 – Apr 12, 39 sap days3920252025: Mar 19 – Apr 22, 45 sap days4520242024: Mar 8 – Apr 8, 52 sap days5220232023: Mar 23 – Apr 27, 37 sap days3720222022: Mar 28 – Apr 29, 31 sap days3120212021: Mar 3 – Apr 4, 47 sap days4720202020: Mar 24 – Apr 24, 41 sap days4120192019: Mar 21 – Apr 20, 36 sap days3620182018: Mar 30 – Apr 30, 45 sap days4520172017: Mar 6 – Apr 8, 35 sap days3520162016: Mar 14 – Apr 14, 34 sap days3420152015: Mar 12 – Apr 14, 36 sap days3620142014: Mar 30 – Apr 26, 27 sap days2720132013: Apr 1 – May 3, 26 sap days2620122012: Feb 15 – Mar 15, 35 sap days3520112011: Mar 26 – Apr 30, 33 sap days3320102010: Feb 27 – Mar 30, 37 sap days3720092009: Mar 20 – Apr 22, 32 sap days3220082008: Mar 21 – Apr 16, 30 sap days3020072007: Mar 12 – Apr 16, 27 sap days2720062006: Mar 12 – Apr 10, 27 sap days2720052005: Mar 8 – Apr 4, 34 sap days3420042004: Mar 16 – Apr 15, 42 sap days4220032003: Mar 14 – Apr 13, 31 sap days3120022002: Mar 16 – Apr 20, 48 sap days4820012001: Mar 19 – Apr 19, 27 sap days2720002000: Feb 25 – Apr 1, 42 sap days4219991999: Mar 9 – Apr 13, 47 sap days4719981998: Mar 5 – Apr 6, 32 sap days3219971997: Mar 24 – Apr 26, 39 sap days3919961996: Mar 30 – May 3, 43 sap days4319951995: Mar 19 – Apr 23, 44 sap days4419941994: Mar 19 – Apr 23, 44 sap days4419931993: Mar 26 – Apr 27, 37 sap days3719921992: Mar 26 – Apr 29, 33 sap days3319911991: Mar 12 – Apr 13, 41 sap days41
Each bar runs from the season's opening signal to its closing signal, estimated from daily temperatures at Merrill. Dashed lines mark the typical dates. The right column counts freeze-thaw sap days from December through May.

Maple production

Lincoln County in the Census of Agriculture

USDA counts maple operations every five years. In Lincoln County the 2022 Census found 38 farms making syrup (-3% since 2017), with taps +6% and syrup output +52% over the same five years. That works out to about 0.35 gallons of syrup per tap in 2022 (0.24 in 2017). Among the 385 counties in this atlas, Lincoln County ranks 57 by taps.

Lincoln County maple production, 2017 and 2022 (USDA Census of Agriculture)
Census yearFarmsTapsGallons of syrupGal / tap
20223852,05218,2930.35
20173949,25812,0320.24

Nearby

Neighboring maple counties

Distances are between reference towns; typical dates are each county's own estimate.

About these numbers

The season dates are estimated from 36 seasons of daily high and low temperatures for the PRISM 4-km grid cell at Merrill (1,276ft), scored with the same freeze-thaw rule as our live forecast: a sap day is an overnight low under 30.2 °F followed by an afternoon high over 37.4 °F. Each season's closing signal is the last sap day before accumulated warmth reaches a threshold, and the opening signal sits five weeks before that, never earlier than the first real freeze-thaw week. Tested against 117 state-seasons of USDA-reported dates, the rule lands within 5.5 days of the reported close and 6.6 days of the reported opening on average, and the typical dates shown here are scaled to Wisconsin's USDA record (12 years). Production figures are copied from the Census as published. Full method, calibration tables and the downloadable dataset →

Sources · 6

  1. 1.2022 Census of Agriculture, County Level Data — Wisconsin, Table 37: Maple Syrup, 2022 and 2017 · USDA National Agricultural Statistics Service
  2. 2.PRISM daily temperature grids (AN81d, 4 km), accessed 2026-10-05 · PRISM Group, Oregon State University, https://prism.oregonstate.edu
  3. 3.Applied Climate Information System (ACIS) web services · NOAA Regional Climate Centers
  4. 4.USDA NASS maple syrup reports — approximate average season opened and closed dates, 2011–2022 · USDA National Agricultural Statistics Service (mirrored by the University of Vermont)
  5. 5.Sap flow in sugar maple: timing and weather drivers (Frontiers in Agronomy, 2025) · de Lima Santos et al.
  6. 6.GeoNames gazetteer (cities500), CC BY 4.0 · GeoNames

FAQ

Lincoln County sugaring questions

When should I tap maple trees in Lincoln County, Wisconsin?
In a typical year the sap starts running around March 21 near Merrill and the season winds down around April 15. Have your taps in a day or two before the first forecast string of freezing nights and 40 °F days. In the past 36 seasons the weather signal came as early as Feb 15 and as late as Apr 1.
How much maple syrup does Lincoln County produce?
The 2022 Census of Agriculture counted 38 maple operations in Lincoln County with 52,052 taps producing 18,293 gallons of syrup, ranking 11 of 60 Wisconsin's counties with published tap counts.
How many sap days does Lincoln County get in a season?
On average 37.1 freeze-thaw sap days from December through May at Merrill, of which about 8.4 are textbook days with a night in the 20s and a day in the 40s. The best season since 1991 was 2024 (52 sap days); the leanest was 2013 (26).
Where do these dates come from?
From 36 seasons of daily high and low temperatures at Merrill (PRISM 4-km grid), scored with the same freeze-thaw rule as our live forecast, then calibrated against USDA's reported season dates for Wisconsin. They describe a typical year at one point in the county; your sugarbush, slope and elevation can shift them by days.

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