Checking current alerts… View NWS forecast and alerts.
Will it freeze in Alpena 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 39°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 39°F Above 36°F · Rain Showers Likely
- Fri, Nov 6 35°F Frost possible · Rain Showers
- Sat, Nov 7 31°F Freeze · Mostly Clear
- Sun, Nov 8 34°F Frost possible · Partly Cloudy
- Mon, Nov 9 39°F Above 36°F · Partly Cloudy
- Tue, Nov 10 34°F Frost possible · Partly Cloudy
- Wed, Nov 11 33°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 Alpena
The median first fall hard-freeze date (28°F) is October 31, from NOAA’s 1991–2020 Climate Normals at Alpena Wastewater Plant. 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 | May 2 · May 17 · May 30 | Sep 20 · Oct 4 · Oct 19 | 141 days |
| 32°F freeze | Apr 21 · May 5 · May 21 | Sep 30 · Oct 17 · Nov 1 | 163 days |
| 28°F hard freeze | Apr 7 · Apr 23 · May 13 | Oct 15 · Oct 31 · Nov 15 | 190 days |
Average high temperature by month
1991–2020 normals at Alpena Wastewater Plant
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 Alpena, MI come from the nearest weather station with freeze statistics in NOAA’s 1991–2020 Climate Normals: Alpena Wastewater Plant (station USW00014814, elevation 590 ft), 1.2 mi from Alpena. 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 Alpena
| City | Distance | Last spring frost | First fall frost |
|---|---|---|---|
| Petoskey, MI | 79 mi | May 6 | Oct 20 |
| Bay City, MI | 105 mi | Apr 27 | Oct 20 |
| Sault Ste. Marie, MI | 107 mi | May 9 | Oct 11 |
| Midland, MI | 107 mi | Apr 29 | Oct 16 |
| Traverse City, MI | 108 mi | May 12 | Oct 16 |
| Cadillac, MI | 113 mi | May 19 | Oct 1 |
| Saginaw, MI | 117 mi | Apr 29 | Oct 21 |
| Frankenmuth, MI | 121 mi | May 3 | Oct 12 |
| Mount Pleasant, MI | 122 mi | Apr 30 | Oct 20 |
| St. Louis, MI | 129 mi | May 1 | Oct 13 |
Frequently asked questions
When is the last frost in Alpena?
On average, the last spring frost (32°F) in Alpena is around May 5. In about 1 year in 10 it comes after May 21, and in 9 years in 10 it comes after April 21.
When is the first frost in Alpena?
The first fall frost (32°F) usually arrives around October 17. There’s a 10% chance of a freeze by September 30 and a 90% chance by November 1.
Can it frost in Alpena 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 17.
What growing zone is Alpena?
Alpena 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 49707. See growing zones in Michigan.
More: all Michigan frost dates · Michigan growing zones · frost vs. freeze