Checking current alerts… View NWS forecast and alerts.
Will it freeze in Mendota in the next 7 nights?
The earliest overnight low at or below 32°F in the available NWS frost forecast is Fri, Nov 6: 29°F (Fri, Nov 6, 6:00 PM CST to Sat, Nov 7, 6:00 AM CST).
Tonight: forecast low 38°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 38°F Above 36°F · Areas Of Drizzle then Mostly Cloudy
- Fri, Nov 6 29°F Freeze · Mostly Clear
- Sat, Nov 7 33°F Frost possible · Mostly Clear
- Sun, Nov 8 34°F Frost possible · Mostly Clear
- Mon, Nov 9 40°F Above 36°F · Mostly Clear
- Tue, Nov 10 38°F Above 36°F · Partly Cloudy
- 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 Mendota
The median first fall hard-freeze date (28°F) is October 25, from NOAA’s 1991–2020 Climate Normals at Paw Paw 2S. 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 23 · May 6 · May 22 | Sep 22 · Oct 5 · Oct 17 | 150 days |
| 32°F freeze | Apr 12 · Apr 27 · May 12 | Sep 30 · Oct 15 · Oct 26 | 171 days |
| 28°F hard freeze | Apr 2 · Apr 15 · May 1 | Oct 13 · Oct 25 · Nov 8 | 193 days |
Average high temperature by month
1991–2020 normals at Paw Paw 2S
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 Mendota, IL come from the nearest weather station with freeze statistics in NOAA’s 1991–2020 Climate Normals: Paw Paw 2S (station USC00116661, elevation 889 ft), 9.8 mi from Mendota. 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 Mendota
| City | Distance | Last spring frost | First fall frost |
|---|---|---|---|
| Peru, IL | 14 mi | Apr 24 | Oct 18 |
| LaSalle, IL | 16 mi | Apr 24 | Oct 18 |
| Spring Valley, IL | 17 mi | Apr 24 | Oct 18 |
| Ottawa, IL | 20 mi | Apr 27 | Oct 17 |
| Princeton, IL | 22 mi | Apr 22 | Oct 17 |
| Rochelle, IL | 25 mi | Apr 26 | Oct 13 |
| Sandwich, IL | 25 mi | Apr 28 | Oct 13 |
| Dixon, IL | 28 mi | Apr 21 | Oct 19 |
| Plano, IL | 30 mi | Apr 28 | Oct 13 |
| DeKalb, IL | 32 mi | Apr 24 | Oct 18 |
Frequently asked questions
When is the last frost in Mendota?
On average, the last spring frost (32°F) in Mendota is around April 27. In about 1 year in 10 it comes after May 12, and in 9 years in 10 it comes after April 12.
When is the first frost in Mendota?
The first fall frost (32°F) usually arrives around October 15. There’s a 10% chance of a freeze by September 30 and a 90% chance by October 26.
Can it frost in Mendota 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 May 6.
What growing zone is Mendota?
Mendota is in USDA Plant Hardiness Zone 5b (average annual extreme minimum temperature −15 to −10°F), based on the 2023 USDA map for ZIP code 61342. See growing zones in Illinois.
More: all Illinois frost dates · Illinois growing zones · frost vs. freeze