Checking current alerts… View NWS forecast and alerts.
Frost forecast
The overnight forecast is unavailable right now. Check back later; the historical frost dates below are not a forecast for tonight.
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 Spirit Lake
The median first fall hard-freeze date (28°F) is October 21, from NOAA’s 1991–2020 Climate Normals at Spirit Lake. 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 25 · May 6 · May 20 | Sep 18 · Oct 1 · Oct 15 | 145 days |
| 32°F freeze | Apr 14 · Apr 28 · May 9 | Sep 27 · Oct 11 · Oct 24 | 164 days |
| 28°F hard freeze | Apr 4 · Apr 19 · May 2 | Oct 6 · Oct 21 · Nov 4 | 183 days |
Average high temperature by month
1991–2020 normals at Spirit Lake
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 Spirit Lake, IA come from the nearest weather station with freeze statistics in NOAA’s 1991–2020 Climate Normals: Spirit Lake (station USC00137859, elevation 1,420 ft), 1.4 mi from Spirit Lake. 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 Spirit Lake
| City | Distance | Last spring frost | First fall frost |
|---|---|---|---|
| Estherville, IA | 14 mi | May 2 | Oct 3 |
| Spencer, IA | 19 mi | May 1 | Oct 3 |
| Worthington, MN | 29 mi | May 3 | Oct 4 |
| Fairmont, MN | 36 mi | Apr 25 | Oct 14 |
| Sheldon, IA | 40 mi | May 5 | Sep 28 |
| Algona, IA | 50 mi | Apr 30 | Oct 6 |
| Cherokee, IA | 51 mi | May 4 | Oct 4 |
| Storm Lake, IA | 53 mi | Apr 25 | Oct 13 |
| Orange City, IA | 55 mi | Apr 30 | Oct 3 |
| Sioux Center, IA | 58 mi | Apr 30 | Oct 3 |
Frequently asked questions
When is the last frost in Spirit Lake?
On average, the last spring frost (32°F) in Spirit Lake is around April 28. In about 1 year in 10 it comes after May 9, and in 9 years in 10 it comes after April 14.
When is the first frost in Spirit Lake?
The first fall frost (32°F) usually arrives around October 11. There’s a 10% chance of a freeze by September 27 and a 90% chance by October 24.
Can it frost in Spirit Lake 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 Spirit Lake?
Spirit Lake is in USDA Plant Hardiness Zone 5a (average annual extreme minimum temperature −20 to −15°F), based on the 2023 USDA map for ZIP code 51360. See growing zones in Iowa.
More: all Iowa frost dates · Iowa growing zones · frost vs. freeze