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Will it freeze in Waterloo in the next 7 nights?
No overnight lows at or below 32°F are forecast in Waterloo during the next 7 nights in the available NWS frost forecast.
Tonight: forecast low 45°F. Above 36°F.
NWS forecast period: Thu, Nov 5, 6:00 PM CST to Fri, Nov 6, 6:00 AM CST.
2 of the next 7 nights are forecast at 36°F or colder, cold enough for frost on exposed plants.
- Tonight 45°F Above 36°F · Slight Chance Drizzle then Cloudy
- Fri, Nov 6 33°F Frost possible · Mostly Clear
- Sat, Nov 7 33°F Frost possible · Mostly Clear
- Sun, Nov 8 37°F Above 36°F · Clear
- Mon, Nov 9 41°F Above 36°F · Clear
- Tue, Nov 10 42°F Above 36°F · Mostly Clear
- Wed, Nov 11 43°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 Waterloo
The median first fall hard-freeze date (28°F) is November 5, from NOAA’s 1991–2020 Climate Normals at Festus. 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 5 · Apr 22 · May 8 | Oct 4 · Oct 17 · Oct 28 | 174 days |
| 32°F freeze | Mar 25 · Apr 9 · Apr 25 | Oct 14 · Oct 26 · Nov 8 | 197 days |
| 28°F hard freeze | Mar 12 · Mar 31 · Apr 15 | Oct 23 · Nov 5 · Nov 23 | 221 days |
Average high temperature by month
1991–2020 normals at Festus
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 Waterloo, IL come from the nearest weather station with freeze statistics in NOAA’s 1991–2020 Climate Normals: Festus (station USC00232850, elevation 600 ft), 15 mi from Waterloo. 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 Waterloo
| City | Distance | Last spring frost | First fall frost |
|---|---|---|---|
| Columbia, IL | 8.7 mi | Apr 6 | Oct 27 |
| Arnold, MO | 13 mi | Apr 9 | Oct 26 |
| Pevely, MO | 14 mi | Apr 9 | Oct 26 |
| Herculaneum, MO | 14 mi | Apr 9 | Oct 26 |
| Belleville, IL | 15 mi | Apr 12 | Oct 20 |
| Cahokia Heights, IL | 16 mi | Apr 8 | Oct 26 |
| Festus, MO | 16 mi | Apr 9 | Oct 26 |
| Swansea, IL | 17 mi | Apr 12 | Oct 20 |
| East St. Louis, IL | 19 mi | Apr 8 | Oct 26 |
| Sunset Hills, MO | 19 mi | Apr 1 | Nov 4 |
Frequently asked questions
When is the last frost in Waterloo?
On average, the last spring frost (32°F) in Waterloo is around April 9. In about 1 year in 10 it comes after April 25, and in 9 years in 10 it comes after March 25.
When is the first frost in Waterloo?
The first fall frost (32°F) usually arrives around October 26. There’s a 10% chance of a freeze by October 14 and a 90% chance by November 8.
Can it frost in Waterloo 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 22.
What growing zone is Waterloo?
Waterloo is in USDA Plant Hardiness Zone 7a (average annual extreme minimum temperature 0 to 5°F), based on the 2023 USDA map for ZIP code 62298. See growing zones in Illinois.
More: all Illinois frost dates · Illinois growing zones · frost vs. freeze