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Minnesota · county maple atlas

Maple sugaring in Fillmore County, Minnesota

Fillmore County had 5 maple operations and 163 taps in the 2022 Census. Around Preston, sap usually runs from February 26 to March 29. Here's the long-run pattern, 36 seasons of sap weather, and the outlook this week.
Too early to tapAbout 143 days until the usual start.
Sap starts
Feb 26
typical year
Season ends
Mar 29
about 4 weeks
Sap days / season
38.8
1991–2026 average
Taps, 2022
163
#30 of 41 in MN

Sap-flow outlook at Preston right now

Full Minnesota forecast →

Forecast for Preston, MN

Updated Oct 6, 9:06 AM EDT

Off-season for now. Sap needs freezing nights, and none are in sight. Fillmore County's season usually opens around February 26, which is 143 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° / 66°

    0h below · 24h above

    No refreeze forecast
  3. FriOct 9
    46° / 69°

    0h below · 24h above

    No refreeze forecast
  4. SatOct 10
    55° / 76°

    0h below · 24h above

    No refreeze forecast
  5. SunOct 11
    62° / 75°

    0h below · 24h above

    No refreeze forecast
  6. MonOct 12
    57° / 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 Preston

Freeze-thaw weather at Preston peaks in the weeks of Mar 2 to Apr 6, which hold about 47% of a season's sap days. March is the busiest month.
Typical season: Feb 26 – Mar 290246Week of Dec 1: 1.5 sap days on averageWeek of Dec 8: 1.9 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: 0.7 sap days on averageWeek of Jan 5: 1.0 sap days on averageWeek of Jan 12: 0.6 sap days on averageWeek of Jan 19: 0.5 sap days on averageWeek of Jan 26: 1.1 sap days on averageWeek of Feb 2: 1.2 sap days on averageWeek of Feb 9: 1.2 sap days on averageWeek of Feb 16: 1.8 sap days on averageWeek of Feb 23: 1.8 sap days on averageWeek of Mar 2: 2.4 sap days on averageWeek of Mar 9: 2.8 sap days on averageWeek of Mar 16: 3.5 sap days on averageWeek of Mar 23: 3.6 sap days on averageWeek of Mar 30: 3.2 sap days on averageWeek of Apr 6: 2.8 sap days on averageWeek of Apr 13: 1.9 sap days on averageWeek of Apr 20: 1.4 sap days on averageWeek of Apr 27: 1.0 sap days on averageWeek of May 4: 0.4 sap days on averageWeek of May 11: 0.3 sap days on averageWeek of May 18: 0.1 sap days on averageWeek of May 25: 0.0 sap days on averageDecJanFebMarAprMaytaps in ~Feb 26
Average number of freeze-thaw sap days in each week of the season at Preston, 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 8; the middle half of seasons fell between Mar 1 and Mar 16. Earliest Feb 12 (2012), latest Mar 27 (2018).
Closing signal
Median Apr 7; middle half between Mar 31 and Apr 16. Earliest Mar 11 (2012), latest Apr 29 (2018).
Sap days by month
Dec16%Jan9%Feb15%Mar35%Apr22%May3%

36 seasons of sap weather

Fillmore County seasons, 1991–2026

The best sap year at Preston was 2024 with 59 freeze-thaw days; the leanest was 2001 with 22. 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 22 – Mar 29, 39 sap days3920252025: Feb 26 – Apr 2, 51 sap days5120242024: Mar 2 – Apr 6, 59 sap days5920232023: Mar 10 – Apr 7, 49 sap days4920222022: Mar 19 – Apr 20, 46 sap days4620212021: Mar 1 – Apr 2, 53 sap days5320202020: Mar 16 – Apr 20, 52 sap days5220192019: Mar 14 – Apr 16, 37 sap days3720182018: Mar 27 – Apr 29, 54 sap days5420172017: Feb 28 – Apr 1, 30 sap days3020162016: Feb 24 – Mar 30, 39 sap days3920152015: Mar 7 – Apr 4, 31 sap days3120142014: Mar 18 – Apr 19, 28 sap days2820132013: Mar 26 – Apr 24, 35 sap days3520122012: Feb 12 – Mar 11, 45 sap days4520112011: Mar 8 – Apr 7, 25 sap days2520102010: Mar 2 – Mar 30, 24 sap days2420092009: Mar 10 – Apr 12, 40 sap days4020082008: Mar 19 – Apr 16, 29 sap days2920072007: Feb 27 – Mar 23, 41 sap days4120062006: Mar 8 – Apr 9, 34 sap days3420052005: Mar 3 – Apr 3, 39 sap days3920042004: Mar 3 – Apr 7, 42 sap days4220032003: Feb 26 – Mar 31, 37 sap days3720022002: Mar 9 – Apr 6, 49 sap days4920012001: Mar 16 – Apr 18, 22 sap days2220002000: Feb 16 – Mar 18, 41 sap days4119991999: Mar 1 – Mar 30, 41 sap days4119981998: Mar 20 – Mar 25, 24 sap days2419971997: Mar 13 – Apr 17, 36 sap days3619961996: Mar 19 – Apr 22, 47 sap days4719951995: Mar 4 – Apr 6, 30 sap days3019941994: Mar 11 – Apr 11, 41 sap days4119931993: Mar 20 – Apr 22, 31 sap days3119921992: Mar 12 – Apr 14, 38 sap days3819911991: Mar 1 – Mar 31, 36 sap days36
Each bar runs from the season's opening signal to its closing signal, estimated from daily temperatures at Preston. Dashed lines mark the typical dates. The right column counts freeze-thaw sap days from December through May.

Maple production

Fillmore County in the Census of Agriculture

USDA counts maple operations every five years. In Fillmore County the 2022 Census found 5 farms making syrup (+25% since 2017), with taps -89% and syrup output -78% over the same five years. That works out to about 0.23 gallons of syrup per tap in 2022 (0.12 in 2017). Among the 385 counties in this atlas, Fillmore County ranks 351 by taps.

Fillmore County maple production, 2017 and 2022 (USDA Census of Agriculture)
Census yearFarmsTapsGallons of syrupGal / tap
20225163380.23
201741,4801720.12

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 Preston (1,033ft), 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 Minnesota's USDA record (3 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 — Minnesota, 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

Fillmore County sugaring questions

When should I tap maple trees in Fillmore County, Minnesota?
In a typical year the sap starts running around February 26 near Preston and the season winds down around March 29. 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 12 and as late as Mar 27.
How much maple syrup does Fillmore County produce?
The 2022 Census of Agriculture counted 5 maple operations in Fillmore County with 163 taps producing 38 gallons of syrup, ranking 30 of 41 Minnesota's counties with published tap counts.
How many sap days does Fillmore County get in a season?
On average 38.8 freeze-thaw sap days from December through May at Preston, of which about 10.8 are textbook days with a night in the 20s and a day in the 40s. The best season since 1991 was 2024 (59 sap days); the leanest was 2001 (22).
Where do these dates come from?
From 36 seasons of daily high and low temperatures at Preston (PRISM 4-km grid), scored with the same freeze-thaw rule as our live forecast, then calibrated against USDA's reported season dates for Minnesota. 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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