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Will it freeze in Mount Zion in the next 7 nights?
The earliest overnight low at or below 32°F in the available NWS frost forecast is Fri, Nov 6: 28°F (Fri, Nov 6, 6:00 PM CST to Sat, Nov 7, 6:00 AM CST).
Tonight: forecast low 39°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 39°F Above 36°F · Chance Drizzle
- Fri, Nov 6 28°F Hard freeze · Mostly Clear
- Sat, Nov 7 30°F Freeze · Mostly Clear
- Sun, Nov 8 33°F Frost possible · Clear
- Mon, Nov 9 38°F Above 36°F · Mostly Clear
- Tue, Nov 10 38°F Above 36°F · Mostly Clear
- Wed, Nov 11 38°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 Mount Zion
The median first fall hard-freeze date (28°F) is November 2, from NOAA’s 1991–2020 Climate Normals at Decatur Airport. 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 13 · Apr 26 · May 12 | Sep 26 · Oct 11 · Oct 23 | 164 days |
| 32°F freeze | Apr 3 · Apr 16 · Apr 30 | Oct 7 · Oct 22 · Nov 3 | 187 days |
| 28°F hard freeze | Mar 20 · Apr 5 · Apr 21 | Oct 21 · Nov 2 · Nov 17 | 210 days |
Average high temperature by month
1991–2020 normals at Decatur Airport
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 Mount Zion, IL come from the nearest weather station with freeze statistics in NOAA’s 1991–2020 Climate Normals: Decatur Airport (station USW00003887, elevation 675 ft), 3.6 mi from Mount Zion. 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 Mount Zion
| City | Distance | Last spring frost | First fall frost |
|---|---|---|---|
| Decatur, IL | 5.6 mi | Apr 14 | Oct 24 |
| Monticello, IL | 24 mi | Apr 23 | Oct 13 |
| Clinton, IL | 25 mi | Apr 20 | Oct 16 |
| Taylorville, IL | 27 mi | Apr 12 | Oct 20 |
| Pana, IL | 29 mi | Apr 17 | Oct 23 |
| Mattoon, IL | 35 mi | Apr 11 | Oct 29 |
| Lincoln, IL | 36 mi | Apr 20 | Oct 16 |
| Mahomet, IL | 39 mi | Apr 23 | Oct 13 |
| Savoy, IL | 39 mi | Apr 19 | Oct 17 |
| Champaign, IL | 40 mi | Apr 15 | Oct 24 |
Frequently asked questions
When is the last frost in Mount Zion?
On average, the last spring frost (32°F) in Mount Zion is around April 16. In about 1 year in 10 it comes after April 30, and in 9 years in 10 it comes after April 3.
When is the first frost in Mount Zion?
The first fall frost (32°F) usually arrives around October 22. There’s a 10% chance of a freeze by October 7 and a 90% chance by November 3.
Can it frost in Mount Zion 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 26.
What growing zone is Mount Zion?
Mount Zion 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 62549. See growing zones in Illinois.
More: all Illinois frost dates · Illinois growing zones · frost vs. freeze