Checking current alerts… View NWS forecast and alerts.
Will it freeze in Caldwell in the next 7 nights?
The earliest overnight low at or below 32°F in the available NWS frost forecast is Tonight: 30°F (Thu, Nov 5, 6:00 PM MST to Fri, Nov 6, 6:00 AM MST).
Tonight: forecast low 30°F. Freeze.
NWS forecast period: Thu, Nov 5, 6:00 PM MST to Fri, Nov 6, 6:00 AM MST.
4 of the next 7 nights are forecast at 36°F or colder, cold enough for frost on exposed plants.
- Tonight 30°F Freeze · Mostly Clear then Patchy Fog
- Fri, Nov 6 32°F Freeze · Partly Cloudy
- Sat, Nov 7 39°F Above 36°F · Mostly Clear
- Sun, Nov 8 35°F Frost possible · Mostly Cloudy then Patchy Fog
- Mon, Nov 9 36°F Frost possible · Partly Cloudy then Patchy Fog
- Tue, Nov 10 38°F Above 36°F · Partly Cloudy
- Wed, Nov 11 40°F Above 36°F · 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 Caldwell
The median first fall hard-freeze date (28°F) is October 25, from NOAA’s 1991–2020 Climate Normals at Nampa Sugar Factory. 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 1 · May 16 · Jun 6 | Sep 15 · Sep 30 · Oct 14 | 134 days |
| 32°F freeze | Apr 15 · Apr 29 · May 18 | Sep 29 · Oct 13 · Oct 28 | 164 days |
| 28°F hard freeze | Mar 25 · Apr 11 · May 1 | Oct 9 · Oct 25 · Nov 10 | 195 days |
Average high temperature by month
1991–2020 normals at Nampa Sugar Factory
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 Caldwell, ID come from the nearest weather station with freeze statistics in NOAA’s 1991–2020 Climate Normals: Nampa Sugar Factory (station USC00106305, elevation 2,470 ft), 5.1 mi from Caldwell. 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 Caldwell
| City | Distance | Last spring frost | First fall frost |
|---|---|---|---|
| Middleton, ID | 5.0 mi | Apr 29 | Oct 13 |
| Nampa, ID | 6.2 mi | Apr 29 | Oct 13 |
| Star, ID | 9.3 mi | Apr 29 | Oct 13 |
| Eagle, ID | 13 mi | Apr 29 | Oct 13 |
| Meridian, ID | 13 mi | Apr 24 | Oct 21 |
| Kuna, ID | 16 mi | Apr 24 | Oct 21 |
| Emmett, ID | 17 mi | Apr 30 | Oct 17 |
| Garden City, ID | 18 mi | May 17 | Oct 12 |
| Boise, ID | 22 mi | Apr 24 | Oct 21 |
| Fruitland, ID | 29 mi | Apr 22 | Oct 9 |
Frequently asked questions
When is the last frost in Caldwell?
On average, the last spring frost (32°F) in Caldwell is around April 29. In about 1 year in 10 it comes after May 18, and in 9 years in 10 it comes after April 15.
When is the first frost in Caldwell?
The first fall frost (32°F) usually arrives around October 13. There’s a 10% chance of a freeze by September 29 and a 90% chance by October 28.
Can it frost in Caldwell 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 16.
What growing zone is Caldwell?
Caldwell 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 83605. See growing zones in Idaho.
More: all Idaho frost dates · Idaho growing zones · UV index today in Caldwell · frost vs. freeze