Illinois · live outlook · refreshes every 3 h

Illinois sap flow forecast

The next several days for Illinois' sugaring country, read the way a sugarmaker reads them: how cold the night gets, how warm the afternoon gets, and whether that adds up to a run.

Illinois highlighted on a map of the maple belt, with its forecast towns (Funks Grove, Simpson) marked — Illinois in the maple beltDots: Funks Grove · Simpson

Season opens: early January (south) to mid-February (central); typical
Closes: late February (south) to mid-March (central); typical

Funks Grove · Central Illinois reference point: Funks Grove in McLean County, a ~4,000-tree, 500-acre sugarbush that historically ran mid-February to mid-March (WGLT, 2023).

Forecast for Funks Grove

Updated Nov 10, 6:16 AM EST

3 sap days in the next 6

freeze thaw 32°F

WedNov 11
42° / 62°
0h below · 24h above
No refreeze forecast
Low of 42°F — no refreeze is forecast. An earlier run may continue, then slow; temperature alone cannot rule out flow.
ThuNov 12
37° / 46°
0h below · 24h above
No refreeze forecast
Low of 37°F — no refreeze is forecast. An earlier run may continue, then slow; temperature alone cannot rule out flow.
FriNov 13
28° / 43°
10h below · 11h above
Classic sap day
Low 28°F, high 43°F — nights in the 20s and days in the 40s: the textbook sap day.
SatNov 14
23° / 46°
11h below · 12h above
Classic sap day
Low 23°F, high 46°F — nights in the 20s and days in the 40s: the textbook sap day.
SunNov 15
28° / 50°
7h below · 16h above
Sap likely
Freeze (28°F) then a warm 50°F. A run is possible; watch for a shorter run as the day warms.
MonNov 16
32° / 53°
Run tapering
No overnight freeze (low 32°F). Yesterday's favorable weather may allow a run to continue, then slow without a refreeze.

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

Simpson · Southern Illinois reference point: Illinois Extension's 100-tap sugarbush at the Dixon Springs Agricultural Center in Simpson.

Forecast for Simpson

Updated Nov 10, 8:56 AM EST

3 sap days in the next 6

freeze thaw 32°F

WedNov 11
43° / 71°
0h below · 24h above
No refreeze forecast
Low of 43°F — no refreeze is forecast. An earlier run may continue, then slow; temperature alone cannot rule out flow.
ThuNov 12
42° / 54°
0h below · 24h above
No refreeze forecast
Low of 42°F — no refreeze is forecast. An earlier run may continue, then slow; temperature alone cannot rule out flow.
FriNov 13
29° / 48°
5h below · 17h above
Classic sap day
Low 29°F, high 48°F — nights in the 20s and days in the 40s: the textbook sap day.
SatNov 14
24° / 51°
9h below · 14h above
Sap likely
Freeze (24°F) then a warm 51°F. A run is possible; watch for a shorter run as the day warms.
SunNov 15
28° / 54°
7h below · 17h above
Sap likely
Freeze (28°F) then a warm 54°F. A run is possible; watch for a shorter run as the day warms.
MonNov 16
32° / 58°
Run tapering
No overnight freeze (low 32°F). Yesterday's favorable weather may allow a run to continue, then slow without a refreeze.

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

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Your sugarbush, your forecast

Hourly temperatures for your exact spot, turned into a day-by-day sap-run outlook. US and Canada.

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Data & method · 4

1.National Weather Service API · NOAA National Weather Service
2.Sap flow in sugar maple: timing and weather drivers (Frontiers in Agronomy, 2025) · de Lima Santos et al.
3.Maple Sugaring Tips for Beginners and Backyard Maple Sugar Producers · UNH Extension
4.North American Maple Syrup Producers Manual, 2nd ed. (Bulletin 856) · The Ohio State University Extension

LuckySap · free on iPhone & Android

Never miss the first run

LuckySap can ping you the evening before a strong sap day, then keeps your collections, sugar readings and boils in one season log. Free on iPhone and Android.