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Michigan · county maple atlas

Maple sugaring in Iron County, Michigan

Iron County had 5 maple operations and 9,930 taps in the 2022 Census. Around Crystal Falls, sap usually runs from March 23 to April 25. Here's the long-run pattern, 36 seasons of sap weather, and the outlook this week.
Too early to tapAbout 168 days until the usual start.
Sap starts
Mar 23
typical year
Season ends
Apr 25
about 5 weeks
Sap days / season
43.4
1991–2026 average
Taps, 2022
9,930
#20 of 66 in MI

Sap-flow outlook at Crystal Falls right now

Full Michigan forecast →

Forecast for Crystal Falls, MI

Updated Oct 6, 10:24 AM EDT

Off-season for now. Sap needs freezing nights, and none are in sight. Iron County's season usually opens around March 23, which is 168 days away.

No freeze-thaw days in the forecast

freeze thaw 32°F

  1. WedOct 7
    43° / 66°

    0h below · 24h above

    No refreeze forecast
  2. ThuOct 8
    36° / 60°

    0h below · 24h above

    No refreeze forecast
  3. FriOct 9
    32° / 62°

    0h below · 22h above

    No refreeze forecast
  4. SatOct 10
    37° / 72°

    0h below · 24h above

    No refreeze forecast
  5. SunOct 11
    52° / 75°

    0h below · 24h above

    No refreeze forecast
  6. MonOct 12
    43° / 60°
    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 Crystal Falls

Freeze-thaw weather at Crystal Falls peaks in the weeks of Mar 16 to Apr 27, which hold about 57% of a season's sap days. April is the busiest month.
Typical season: Mar 23 – Apr 250246Week of Dec 1: 0.8 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: 0.6 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: 0.4 sap days on averageWeek of Jan 19: 0.2 sap days on averageWeek of Jan 26: 0.4 sap days on averageWeek of Feb 2: 1.0 sap days on averageWeek of Feb 9: 0.8 sap days on averageWeek of Feb 16: 1.1 sap days on averageWeek of Feb 23: 1.3 sap days on averageWeek of Mar 2: 2.2 sap days on averageWeek of Mar 9: 2.4 sap days on averageWeek of Mar 16: 2.8 sap days on averageWeek of Mar 23: 3.4 sap days on averageWeek of Mar 30: 3.8 sap days on averageWeek of Apr 6: 4.1 sap days on averageWeek of Apr 13: 3.4 sap days on averageWeek of Apr 20: 4.2 sap days on averageWeek of Apr 27: 3.1 sap days on averageWeek of May 4: 1.9 sap days on averageWeek of May 11: 1.5 sap days on averageWeek of May 18: 0.9 sap days on averageWeek of May 25: 0.5 sap days on averageDecJanFebMarAprMaytaps in ~Mar 23
Average number of freeze-thaw sap days in each week of the season at Crystal Falls, 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 27; the middle half of seasons fell between Mar 18 and Mar 31. Earliest Feb 17 (2012), latest Apr 10 (1996).
Closing signal
Median Apr 28; middle half between Apr 20 and May 3. Earliest Mar 18 (2012), latest May 14 (1996).
Sap days by month
Dec7%Jan4%Feb9%Mar28%Apr38%May13%

36 seasons of sap weather

Iron County seasons, 1991–2026

The best sap year at Crystal Falls was 2024 with 58 freeze-thaw days; the leanest was 2014 with 29. 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 19 – Apr 22, 44 sap days4420252025: Mar 26 – Apr 30, 44 sap days4420242024: Mar 13 – Apr 17, 58 sap days5820232023: Mar 31 – Apr 27, 38 sap days3820222022: Apr 4 – May 6, 36 sap days3620212021: Mar 8 – Apr 5, 50 sap days5020202020: Apr 2 – May 7, 53 sap days5320192019: Mar 31 – May 3, 41 sap days4120182018: Apr 2 – Apr 30, 44 sap days4420172017: Mar 16 – Apr 19, 50 sap days5020162016: Mar 18 – Apr 15, 41 sap days4120152015: Mar 24 – Apr 28, 40 sap days4020142014: Apr 5 – May 6, 29 sap days2920132013: Apr 4 – May 6, 32 sap days3220122012: Feb 17 – Mar 18, 48 sap days4820112011: Apr 1 – May 4, 40 sap days4020102010: Mar 3 – Mar 31, 45 sap days4520092009: Mar 28 – May 2, 47 sap days4720082008: Apr 1 – May 6, 39 sap days3920072007: Mar 18 – Apr 20, 35 sap days3520062006: Mar 15 – Apr 18, 35 sap days3520052005: Mar 13 – Apr 16, 49 sap days4920042004: Apr 1 – May 6, 50 sap days5020032003: Mar 23 – Apr 27, 42 sap days4220022002: Mar 30 – May 3, 49 sap days4920012001: Mar 23 – Apr 27, 33 sap days3320002000: Mar 20 – Apr 24, 52 sap days5219991999: Mar 21 – Apr 25, 50 sap days5019981998: Mar 10 – Apr 11, 44 sap days4419971997: Mar 30 – May 4, 39 sap days3919961996: Apr 10 – May 14, 39 sap days3919951995: Mar 30 – Apr 30, 50 sap days5019941994: Mar 29 – May 3, 56 sap days5619931993: Mar 30 – Apr 27, 42 sap days4219921992: Mar 30 – Apr 29, 35 sap days3519911991: Mar 21 – Apr 25, 45 sap days45
Each bar runs from the season's opening signal to its closing signal, estimated from daily temperatures at Crystal Falls. Dashed lines mark the typical dates. The right column counts freeze-thaw sap days from December through May.

Maple production

Iron County in the Census of Agriculture

USDA counts maple operations every five years. In Iron County the 2022 Census found 5 farms making syrup (-17% since 2017), with taps +52% and syrup output +265% over the same five years. That works out to about 0.46 gallons of syrup per tap in 2022 (0.19 in 2017). Among the 385 counties in this atlas, Iron County ranks 139 by taps.

Iron County maple production, 2017 and 2022 (USDA Census of Agriculture)
Census yearFarmsTapsGallons of syrupGal / tap
202259,9304,5330.46
201766,5451,2430.19

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 Crystal Falls (1,401ft), 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 Michigan'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 — Michigan, 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

Iron County sugaring questions

When should I tap maple trees in Iron County, Michigan?
In a typical year the sap starts running around March 23 near Crystal Falls and the season winds down around April 25. 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 17 and as late as Apr 10.
How much maple syrup does Iron County produce?
The 2022 Census of Agriculture counted 5 maple operations in Iron County with 9,930 taps producing 4,533 gallons of syrup, ranking 20 of 66 Michigan's counties with published tap counts.
How many sap days does Iron County get in a season?
On average 43.4 freeze-thaw sap days from December through May at Crystal Falls, of which about 8.3 are textbook days with a night in the 20s and a day in the 40s. The best season since 1991 was 2024 (58 sap days); the leanest was 2014 (29).
Where do these dates come from?
From 36 seasons of daily high and low temperatures at Crystal Falls (PRISM 4-km grid), scored with the same freeze-thaw rule as our live forecast, then calibrated against USDA's reported season dates for Michigan. 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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