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Minnesota · county maple atlas

Maple sugaring in Carlton County, Minnesota

Carlton County had 17 maple operations and 4,706 taps in the 2022 Census, number 5 in Minnesota. Around Carlton, sap usually runs from March 13 to April 16. Here's the long-run pattern, 36 seasons of sap weather, and the outlook this week.
Too early to tapAbout 158 days until the usual start.
Sap starts
Mar 13
typical year
Season ends
Apr 16
about 5 weeks
Sap days / season
36.1
1991–2026 average
Taps, 2022
4,706
#5 of 41 in MN

Sap-flow outlook at Carlton right now

Full Minnesota forecast →

Forecast for Carlton, MN

Updated Oct 6, 10:51 AM EDT

Off-season for now. Sap needs freezing nights, and none are in sight. Carlton County's season usually opens around March 13, which is 158 days away.

No freeze-thaw days in the forecast

freeze thaw 32°F

  1. WedOct 7
    45° / 66°

    0h below · 24h above

    No refreeze forecast
  2. ThuOct 8
    40° / 62°

    0h below · 24h above

    No refreeze forecast
  3. FriOct 9
    40° / 63°

    0h below · 24h above

    No refreeze forecast
  4. SatOct 10
    48° / 73°

    0h below · 24h above

    No refreeze forecast
  5. SunOct 11
    56° / 66°

    0h below · 24h above

    No refreeze forecast
  6. MonOct 12
    46° / 53°
    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 Carlton

Freeze-thaw weather at Carlton peaks in the weeks of Mar 9 to Apr 27, which hold about 63% of a season's sap days. April is the busiest month.
Typical season: Mar 13 – Apr 160246Week of Dec 1: 0.8 sap days on averageWeek of Dec 8: 1.0 sap days on averageWeek of Dec 15: 0.5 sap days on averageWeek of Dec 22: 0.5 sap days on averageWeek of Dec 29: 0.2 sap days on averageWeek of Jan 5: 0.4 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: 0.6 sap days on averageWeek of Feb 2: 0.9 sap days on averageWeek of Feb 9: 0.8 sap days on averageWeek of Feb 16: 1.2 sap days on averageWeek of Feb 23: 1.2 sap days on averageWeek of Mar 2: 1.9 sap days on averageWeek of Mar 9: 2.1 sap days on averageWeek of Mar 16: 2.7 sap days on averageWeek of Mar 23: 3.2 sap days on averageWeek of Mar 30: 3.4 sap days on averageWeek of Apr 6: 3.1 sap days on averageWeek of Apr 13: 2.8 sap days on averageWeek of Apr 20: 3.2 sap days on averageWeek of Apr 27: 2.3 sap days on averageWeek of May 4: 1.4 sap days on averageWeek of May 11: 0.8 sap days on averageWeek of May 18: 0.5 sap days on averageWeek of May 25: 0.2 sap days on averageDecJanFebMarAprMaytaps in ~Mar 13
Average number of freeze-thaw sap days in each week of the season at Carlton, 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 23; the middle half of seasons fell between Mar 14 and Mar 29. Earliest Feb 18 (2012), latest Apr 9 (2013).
Closing signal
Median Apr 25; middle half between Apr 15 and Apr 30. Earliest Mar 17 (2012), latest May 13 (2013).
Sap days by month
Dec8%Jan4%Feb11%Mar31%Apr36%May10%

36 seasons of sap weather

Carlton County seasons, 1991–2026

The best sap year at Carlton was 2002 with 49 freeze-thaw days; the leanest was 2001 with 24. 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 20 – Apr 21, 46 sap days4620252025: Mar 20 – Apr 24, 40 sap days4020242024: Mar 12 – Apr 14, 46 sap days4620232023: Apr 3 – May 4, 29 sap days2920222022: Apr 5 – May 6, 31 sap days3120212021: Mar 12 – Apr 16, 46 sap days4620202020: Mar 29 – Apr 26, 40 sap days4020192019: Mar 28 – Apr 30, 35 sap days3520182018: Mar 31 – Apr 29, 43 sap days4320172017: Mar 9 – Apr 13, 38 sap days3820162016: Mar 17 – Apr 14, 33 sap days3320152015: Mar 11 – Apr 11, 30 sap days3020142014: Apr 5 – May 4, 24 sap days2420132013: Apr 9 – May 13, 30 sap days3020122012: Feb 18 – Mar 17, 35 sap days3520112011: Mar 26 – Apr 29, 31 sap days3120102010: Mar 2 – Mar 30, 36 sap days3620092009: Mar 25 – Apr 28, 32 sap days3220082008: Apr 4 – May 9, 32 sap days3220072007: Mar 19 – Apr 19, 33 sap days3320062006: Mar 15 – Apr 10, 29 sap days2920052005: Mar 12 – Apr 15, 36 sap days3620042004: Mar 26 – Apr 29, 42 sap days4220032003: Mar 21 – Apr 24, 37 sap days3720022002: Mar 30 – May 4, 49 sap days4920012001: Mar 26 – Apr 27, 24 sap days2420002000: Mar 3 – Apr 6, 38 sap days3819991999: Mar 17 – Apr 20, 46 sap days4619981998: Mar 10 – Apr 11, 31 sap days3119971997: Mar 29 – May 2, 33 sap days3319961996: Apr 6 – May 7, 35 sap days3519951995: Mar 29 – May 1, 42 sap days4219941994: Mar 19 – Apr 22, 39 sap days3919931993: Mar 28 – Apr 26, 35 sap days3519921992: Mar 29 – Apr 28, 35 sap days3519911991: Mar 15 – Apr 19, 37 sap days37
Each bar runs from the season's opening signal to its closing signal, estimated from daily temperatures at Carlton. Dashed lines mark the typical dates. The right column counts freeze-thaw sap days from December through May.

Maple production

Carlton County in the Census of Agriculture

USDA counts maple operations every five years. In Carlton County the 2022 Census found 17 farms making syrup (+42% since 2017), with taps -6% and syrup output +28% over the same five years. That works out to about 0.23 gallons of syrup per tap in 2022 (0.17 in 2017). Among the 385 counties in this atlas, Carlton County ranks 197 by taps.

Carlton County maple production, 2017 and 2022 (USDA Census of Agriculture)
Census yearFarmsTapsGallons of syrupGal / tap
2022174,7061,0890.23
2017125,0148510.17

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 Carlton (1,079ft), 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

Carlton County sugaring questions

When should I tap maple trees in Carlton County, Minnesota?
In a typical year the sap starts running around March 13 near Carlton and the season winds down around April 16. 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 18 and as late as Apr 9.
How much maple syrup does Carlton County produce?
The 2022 Census of Agriculture counted 17 maple operations in Carlton County with 4,706 taps producing 1,089 gallons of syrup, ranking 5 of 41 Minnesota's counties with published tap counts.
How many sap days does Carlton County get in a season?
On average 36.1 freeze-thaw sap days from December through May at Carlton, of which about 9.3 are textbook days with a night in the 20s and a day in the 40s. The best season since 1991 was 2002 (49 sap days); the leanest was 2001 (24).
Where do these dates come from?
From 36 seasons of daily high and low temperatures at Carlton (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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