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Will it freeze in St. Clair in the next 7 nights?
The earliest overnight low at or below 32°F in the available NWS frost forecast is Sat, Nov 7: 31°F (Sat, Nov 7, 6:00 PM EST to Sun, Nov 8, 6:00 AM EST).
Tonight: forecast low 41°F. Above 36°F.
NWS forecast period: Thu, Nov 5, 6:00 PM EST to Fri, Nov 6, 6:00 AM EST.
5 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 · Light Rain Likely
- Fri, Nov 6 36°F Frost possible · Light Rain Likely
- Sat, Nov 7 31°F Freeze · Partly Cloudy
- Sun, Nov 8 33°F Frost possible · Mostly Clear
- Mon, Nov 9 40°F Above 36°F · Partly Cloudy
- Tue, Nov 10 35°F Frost possible · Partly Cloudy
- Wed, Nov 11 34°F Frost possible · Mostly 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 St. Clair
The median first fall hard-freeze date (28°F) is November 12, from NOAA’s 1991–2020 Climate Normals at Port Huron. 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 18 · May 1 · May 18 | Oct 6 · Oct 22 · Nov 4 | 172 days |
| 32°F freeze | Apr 7 · Apr 19 · May 4 | Oct 20 · Nov 3 · Nov 16 | 196 days |
| 28°F hard freeze | Mar 25 · Apr 7 · Apr 21 | Nov 1 · Nov 12 · Nov 28 | 219 days |
Average high temperature by month
1991–2020 normals at Port Huron
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 St. Clair, MI come from the nearest weather station with freeze statistics in NOAA’s 1991–2020 Climate Normals: Port Huron (station USC00206680, elevation 590 ft), 11 mi from St. Clair. 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 St. Clair
| City | Distance | Last spring frost | First fall frost |
|---|---|---|---|
| Marysville, MI | 5.6 mi | Apr 19 | Nov 3 |
| Port Huron, MI | 12 mi | Apr 19 | Nov 3 |
| Richmond, MI | 13 mi | May 1 | Oct 20 |
| New Baltimore, MI | 16 mi | Apr 30 | Oct 24 |
| New Haven, MI | 17 mi | Apr 30 | Oct 24 |
| Mount Clemens, MI | 25 mi | Apr 30 | Oct 24 |
| Utica, MI | 30 mi | Apr 30 | Oct 24 |
| Fraser, MI | 30 mi | Apr 30 | Oct 24 |
| St. Clair Shores, MI | 30 mi | Apr 29 | Oct 22 |
| Roseville, MI | 32 mi | Apr 29 | Oct 22 |
Frequently asked questions
When is the last frost in St. Clair?
On average, the last spring frost (32°F) in St. Clair is around April 19. In about 1 year in 10 it comes after May 4, and in 9 years in 10 it comes after April 7.
When is the first frost in St. Clair?
The first fall frost (32°F) usually arrives around November 3. There’s a 10% chance of a freeze by October 20 and a 90% chance by November 16.
Can it frost in St. Clair 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 1.
What growing zone is St. Clair?
St. Clair 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 48079. See growing zones in Michigan.
More: all Michigan frost dates · Michigan growing zones · frost vs. freeze