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Will it freeze in Rupert in the next 7 nights?
The earliest overnight low at or below 32°F in the available NWS frost forecast is Tonight: 31°F (Thu, Nov 5, 6:00 PM MST to Fri, Nov 6, 6:00 AM MST).
Tonight: forecast low 31°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 31°F Freeze · Areas Of Fog
- Fri, Nov 6 33°F Frost possible · Partly Cloudy
- Sat, Nov 7 35°F Frost possible · Mostly Clear
- Sun, Nov 8 36°F Frost possible · Partly Cloudy
- Mon, Nov 9 39°F Above 36°F · Partly Cloudy
- Tue, Nov 10 39°F Above 36°F · Mostly Clear
- Wed, Nov 11 39°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 Rupert
The median first fall hard-freeze date (28°F) is October 18, from NOAA’s 1991–2020 Climate Normals at Paul 1ENE. 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 7 · May 22 · Jun 12 | Sep 7 · Sep 24 · Oct 8 | 123 days |
| 32°F freeze | Apr 23 · May 6 · May 22 | Sep 22 · Oct 6 · Oct 19 | 151 days |
| 28°F hard freeze | Apr 7 · Apr 22 · May 7 | Oct 3 · Oct 18 · Nov 1 | 177 days |
Average high temperature by month
1991–2020 normals at Paul 1ENE
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 Rupert, ID come from the nearest weather station with freeze statistics in NOAA’s 1991–2020 Climate Normals: Paul 1ENE (station USC00106877, elevation 4,150 ft), 4.5 mi from Rupert. 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 Rupert
| City | Distance | Last spring frost | First fall frost |
|---|---|---|---|
| Burley, ID | 8.1 mi | May 7 | Oct 4 |
| Kimberly, ID | 36 mi | May 6 | Oct 3 |
| Twin Falls, ID | 40 mi | Apr 30 | Oct 9 |
| Jerome, ID | 43 mi | May 2 | Oct 14 |
| Pocatello, ID | 64 mi | May 2 | Oct 11 |
| Chubbuck, ID | 65 mi | May 16 | Oct 2 |
| Hailey, ID | 70 mi | May 13 | Oct 2 |
| Blackfoot, ID | 78 mi | May 5 | Oct 3 |
| Shelley, ID | 94 mi | May 23 | Sep 20 |
| Tremonton, UT | 98 mi | Apr 24 | Oct 17 |
Frequently asked questions
When is the last frost in Rupert?
On average, the last spring frost (32°F) in Rupert is around May 6. In about 1 year in 10 it comes after May 22, and in 9 years in 10 it comes after April 23.
When is the first frost in Rupert?
The first fall frost (32°F) usually arrives around October 6. There’s a 10% chance of a freeze by September 22 and a 90% chance by October 19.
Can it frost in Rupert 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 22.
What growing zone is Rupert?
Rupert 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 83347. See growing zones in Idaho.
More: all Idaho frost dates · Idaho growing zones · frost vs. freeze