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Will it freeze in Roscoe in the next 7 nights?
The earliest overnight low at or below 32°F in the available NWS frost forecast is Fri, Nov 6: 26°F (Fri, Nov 6, 6:00 PM CST to Sat, Nov 7, 6:00 AM CST).
Tonight: forecast low 35°F. Frost possible.
NWS forecast period: Thu, Nov 5, 6:00 PM CST to Fri, Nov 6, 6:00 AM CST.
6 of the next 7 nights are forecast at 36°F or colder, cold enough for frost on exposed plants.
- Tonight 35°F Frost possible · Patchy Drizzle then Mostly Cloudy
- Fri, Nov 6 26°F Hard freeze · Mostly Clear
- Sat, Nov 7 30°F Freeze · Partly Cloudy
- Sun, Nov 8 32°F Freeze · Mostly Clear
- Mon, Nov 9 38°F Above 36°F · Mostly Clear
- Tue, Nov 10 35°F Frost possible · Partly Cloudy
- Wed, Nov 11 36°F Frost possible · Partly Cloudy
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 Roscoe
The median first fall hard-freeze date (28°F) is October 23, from NOAA’s 1991–2020 Climate Normals at Beloit. 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 29 · May 11 · May 27 | Sep 21 · Oct 1 · Oct 14 | 143 days |
| 32°F freeze | Apr 17 · May 1 · May 16 | Sep 28 · Oct 12 · Oct 24 | 162 days |
| 28°F hard freeze | Apr 4 · Apr 20 · May 4 | Oct 9 · Oct 23 · Nov 4 | 186 days |
Average high temperature by month
1991–2020 normals at Beloit
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 Roscoe, IL come from the nearest weather station with freeze statistics in NOAA’s 1991–2020 Climate Normals: Beloit (station USC00470696, elevation 788 ft), 5.5 mi from Roscoe. 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 Roscoe
| City | Distance | Last spring frost | First fall frost |
|---|---|---|---|
| Rockton, IL | 3.1 mi | May 1 | Oct 12 |
| Machesney Park, IL | 4.3 mi | May 1 | Oct 12 |
| South Beloit, IL | 4.3 mi | May 1 | Oct 12 |
| Loves Park, IL | 6.2 mi | Apr 24 | Oct 17 |
| Beloit, WI | 6.8 mi | May 1 | Oct 12 |
| Poplar Grove, IL | 9.9 mi | Apr 28 | Oct 12 |
| Rockford, IL | 12 mi | Apr 24 | Oct 17 |
| Belvidere, IL | 12 mi | Apr 24 | Oct 17 |
| Janesville, WI | 18 mi | Apr 26 | Oct 15 |
| Harvard, IL | 20 mi | Apr 28 | Oct 12 |
Frequently asked questions
When is the last frost in Roscoe?
On average, the last spring frost (32°F) in Roscoe is around May 1. In about 1 year in 10 it comes after May 16, and in 9 years in 10 it comes after April 17.
When is the first frost in Roscoe?
The first fall frost (32°F) usually arrives around October 12. There’s a 10% chance of a freeze by September 28 and a 90% chance by October 24.
Can it frost in Roscoe 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 11.
What growing zone is Roscoe?
Roscoe 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 61073. See growing zones in Illinois.
More: all Illinois frost dates · Illinois growing zones · frost vs. freeze