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Wisconsin · county maple atlas

Maple sugaring in Grant County, Wisconsin

Grant County had 19 maple operations and 1,307 taps in the 2022 Census. Around Lancaster, sap usually runs from March 5 to March 31. Here's the long-run pattern, 36 seasons of sap weather, and the outlook this week.
Too early to tapAbout 150 days until the usual start.
Sap starts
Mar 5
typical year
Season ends
Mar 31
about 4 weeks
Sap days / season
33.7
1991–2026 average
Taps, 2022
1,307
#39 of 60 in WI

Sap-flow outlook at Lancaster right now

Full Wisconsin forecast →

Forecast for Lancaster, WI

Updated Oct 6, 9:06 AM EDT

Off-season for now. Sap needs freezing nights, and none are in sight. Grant County's season usually opens around March 5, which is 150 days away.

No freeze-thaw days in the forecast

freeze thaw 32°F

  1. WedOct 7
    53° / 72°

    0h below · 24h above

    No refreeze forecast
  2. ThuOct 8
    48° / 65°

    0h below · 24h above

    No refreeze forecast
  3. FriOct 9
    46° / 68°

    0h below · 24h above

    No refreeze forecast
  4. SatOct 10
    54° / 74°

    0h below · 24h above

    No refreeze forecast
  5. SunOct 11
    59° / 75°

    0h below · 24h above

    No refreeze forecast
  6. MonOct 12
    57° / 68°
    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 Lancaster

Freeze-thaw weather at Lancaster peaks in the weeks of Mar 2 to Mar 30, which hold about 41% of a season's sap days. March is the busiest month.
Typical season: Mar 5 – Mar 310246Week of Dec 1: 1.6 sap days on averageWeek of Dec 8: 1.7 sap days on averageWeek of Dec 15: 1.2 sap days on averageWeek of Dec 22: 1.1 sap days on averageWeek of Dec 29: 0.8 sap days on averageWeek of Jan 5: 1.1 sap days on averageWeek of Jan 12: 0.7 sap days on averageWeek of Jan 19: 0.5 sap days on averageWeek of Jan 26: 0.9 sap days on averageWeek of Feb 2: 1.3 sap days on averageWeek of Feb 9: 1.3 sap days on averageWeek of Feb 16: 1.8 sap days on averageWeek of Feb 23: 1.9 sap days on averageWeek of Mar 2: 2.4 sap days on averageWeek of Mar 9: 2.7 sap days on averageWeek of Mar 16: 3.1 sap days on averageWeek of Mar 23: 3.3 sap days on averageWeek of Mar 30: 2.4 sap days on averageWeek of Apr 6: 1.8 sap days on averageWeek of Apr 13: 1.3 sap days on averageWeek of Apr 20: 0.5 sap days on averageWeek of Apr 27: 0.3 sap days on averageWeek of May 4: 0.1 sap days on averageWeek of May 11: 0.0 sap days on averageWeek of May 18: 0.0 sap days on averageWeek of May 25: 0.0 sap days on averageDecJanFebMarAprMaytaps in ~Mar 5
Average number of freeze-thaw sap days in each week of the season at Lancaster, 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 2; the middle half of seasons fell between Feb 26 and Mar 8. Earliest Feb 5 (2024), latest Mar 23 (2013).
Closing signal
Median Apr 3; middle half between Mar 25 and Apr 7. Earliest Mar 11 (2012), latest Apr 24 (2013).
Sap days by month
Dec18%Jan11%Feb18%Mar37%Apr16%May0%

36 seasons of sap weather

Grant County seasons, 1991–2026

The best sap year at Lancaster was 2002 with 54 freeze-thaw days; the leanest was 2010 with 15. 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: Feb 14 – Mar 19, 39 sap days3920252025: Feb 17 – Mar 24, 35 sap days3520242024: Feb 5 – Mar 12, 47 sap days4720232023: Mar 6 – Apr 7, 43 sap days4320222022: Mar 8 – Apr 9, 38 sap days3820212021: Feb 26 – Apr 2, 35 sap days3520202020: Mar 3 – Apr 6, 51 sap days5120192019: Mar 4 – Apr 3, 34 sap days3420182018: Mar 21 – Apr 20, 54 sap days5420172017: Feb 18 – Mar 23, 24 sap days2420162016: Feb 18 – Mar 23, 29 sap days2920152015: Mar 1 – Apr 4, 17 sap days1720142014: Mar 15 – Apr 19, 26 sap days2620132013: Mar 23 – Apr 24, 26 sap days2620122012: Feb 10 – Mar 11, 46 sap days4620112011: Mar 6 – Apr 5, 28 sap days2820102010: Mar 1 – Mar 30, 15 sap days1520092009: Feb 27 – Apr 3, 33 sap days3320082008: Mar 16 – Apr 16, 24 sap days2420072007: Feb 22 – Mar 21, 34 sap days3420062006: Mar 6 – Apr 9, 37 sap days3720052005: Mar 2 – Mar 28, 38 sap days3820042004: Feb 26 – Mar 24, 37 sap days3720032003: Feb 26 – Apr 1, 29 sap days2920022002: Mar 7 – Apr 7, 54 sap days5420012001: Mar 10 – Apr 3, 22 sap days2220002000: Feb 28 – Mar 15, 39 sap days3919991999: Feb 26 – Mar 27, 35 sap days3519981998: Mar 20 – Mar 25, 21 sap days2119971997: Mar 1 – Mar 31, 28 sap days2819961996: Mar 15 – Apr 17, 39 sap days3919951995: Feb 23 – Mar 30, 26 sap days2619941994: Mar 8 – Apr 8, 34 sap days3419931993: Mar 19 – Apr 21, 25 sap days2519921992: Mar 4 – Apr 6, 39 sap days3919911991: Mar 1 – Apr 2, 31 sap days31
Each bar runs from the season's opening signal to its closing signal, estimated from daily temperatures at Lancaster. Dashed lines mark the typical dates. The right column counts freeze-thaw sap days from December through May.

Maple production

Grant County in the Census of Agriculture

USDA counts maple operations every five years. In Grant County the 2022 Census found 19 farms making syrup (+36% since 2017), with taps -62% and syrup output -63% over the same five years. That works out to about 0.20 gallons of syrup per tap in 2022 (0.21 in 2017). Among the 385 counties in this atlas, Grant County ranks 269 by taps.

Grant County maple production, 2017 and 2022 (USDA Census of Agriculture)
Census yearFarmsTapsGallons of syrupGal / tap
2022191,3072640.20
2017143,4007200.21

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 Lancaster (1,007ft), 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

Grant County sugaring questions

When should I tap maple trees in Grant County, Wisconsin?
In a typical year the sap starts running around March 5 near Lancaster and the season winds down around March 31. 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 5 and as late as Mar 23.
How much maple syrup does Grant County produce?
The 2022 Census of Agriculture counted 19 maple operations in Grant County with 1,307 taps producing 264 gallons of syrup, ranking 39 of 60 Wisconsin's counties with published tap counts.
How many sap days does Grant County get in a season?
On average 33.7 freeze-thaw sap days from December through May at Lancaster, of which about 12 are textbook days with a night in the 20s and a day in the 40s. The best season since 1991 was 2002 (54 sap days); the leanest was 2010 (15).
Where do these dates come from?
From 36 seasons of daily high and low temperatures at Lancaster (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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