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Will it freeze in Mattoon in the next 7 nights?
The earliest overnight low at or below 32°F in the available NWS frost forecast is Fri, Nov 6: 31°F (Fri, Nov 6, 6:00 PM CST to Sat, Nov 7, 6:00 AM CST).
Tonight: forecast low 41°F. Above 36°F.
NWS forecast period: Thu, Nov 5, 6:00 PM CST to Fri, Nov 6, 6:00 AM CST.
3 of the next 7 nights are forecast at 36°F or colder, cold enough for frost on exposed plants.
- Tonight 41°F Above 36°F · Chance Drizzle then Slight Chance Light Rain
- Fri, Nov 6 31°F Freeze · Mostly Clear
- Sat, Nov 7 31°F Freeze · Mostly Clear
- Sun, Nov 8 33°F Frost possible · Clear
- Mon, Nov 9 39°F Above 36°F · Clear
- Tue, Nov 10 38°F Above 36°F · Mostly Clear
- Wed, Nov 11 39°F Above 36°F · Mostly Clear
Overnight lows from the National Weather Service forecast for this location. This covers the available forecast window, not the first freeze of the whole season. Frost can form above 32°F on clear, calm nights.
Frost and freeze probabilities
Freeze dates shift from year to year. Spring percentages describe the chance of a freeze after the stated date; fall percentages describe the chance of a freeze by that date. The 10% spring date is the cautious one: a later freeze happens about 1 year in 10.
These dates describe historical probabilities, not this year’s forecast or the earliest and latest possible freezes. Different weather stations or probability thresholds can produce different published dates for the same city.
Average first hard freeze in Mattoon
The median first fall hard-freeze date (28°F) is November 7, from NOAA’s 1991–2020 Climate Normals at Mattoon. This is the 50% probability date, not a forecast for this year.
| Temperature | Last spring date 90% · 50% · 10% chance of a later freeze | First fall date 10% · 50% · 90% chance of an earlier freeze | Season |
|---|---|---|---|
| 36°F frost possible | Apr 9 · Apr 23 · May 9 | Oct 2 · Oct 19 · Oct 30 | 175 days |
| 32°F freeze | Mar 31 · Apr 11 · Apr 28 | Oct 15 · Oct 29 · Nov 9 | 199 days |
| 28°F hard freeze | Mar 15 · Apr 2 · Apr 17 | Oct 28 · Nov 7 · Nov 21 | 219 days |
Average high temperature by month
1991–2020 normals at Mattoon
Average low temperature by month
Months with lows near or below freezing carry frost risk
Where these frost dates come from
The frost dates for Mattoon, IL come from the nearest weather station with freeze statistics in NOAA’s 1991–2020 Climate Normals: Mattoon (station USC00115430, elevation 701 ft), 0.6 mi from Mattoon. Local conditions (valleys, hilltops, distance to water, city heat) can shift frost dates by days or weeks. The hardiness zone is from the 2023 USDA Plant Hardiness Zone Map (USDA ARS and Oregon State University PRISM). See our methodology.
Frost dates near Mattoon
| City | Distance | Last spring frost | First fall frost |
|---|---|---|---|
| Charleston, IL | 9.9 mi | Apr 15 | Oct 23 |
| Effingham, IL | 27 mi | Apr 13 | Oct 24 |
| Mount Zion, IL | 35 mi | Apr 16 | Oct 22 |
| Paris, IL | 37 mi | Apr 21 | Oct 20 |
| Pana, IL | 39 mi | Apr 17 | Oct 23 |
| Monticello, IL | 40 mi | Apr 23 | Oct 13 |
| Decatur, IL | 40 mi | Apr 14 | Oct 24 |
| Savoy, IL | 40 mi | Apr 19 | Oct 17 |
| Champaign, IL | 44 mi | Apr 15 | Oct 24 |
| Urbana, IL | 45 mi | Apr 15 | Oct 24 |
Frequently asked questions
When is the last frost in Mattoon?
On average, the last spring frost (32°F) in Mattoon is around April 11. In about 1 year in 10 it comes after April 28, and in 9 years in 10 it comes after March 31.
When is the first frost in Mattoon?
The first fall frost (32°F) usually arrives around October 29. There’s a 10% chance of a freeze by October 15 and a 90% chance by November 9.
Can it frost in Mattoon after the last frost date?
Yes. Frost can form on clear, calm nights even when the air stays above 32°F. Temperatures of 36°F or lower, cold enough for frost on exposed plants, have a 50% chance of occurring after April 23.
What growing zone is Mattoon?
Mattoon is in USDA Plant Hardiness Zone 6a (average annual extreme minimum temperature −10 to −5°F), based on the 2023 USDA map for ZIP code 61938. See growing zones in Illinois.
More: all Illinois frost dates · Illinois growing zones · frost vs. freeze