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Will it freeze in Umatilla in the next 7 nights?
No overnight lows at or below 32°F are forecast in Umatilla during the next 7 nights in the available NWS frost forecast.
Tonight: forecast low 35°F. Frost possible.
NWS forecast period: Thu, Nov 5, 6:00 PM PST to Fri, Nov 6, 6:00 AM PST.
2 of the next 7 nights are forecast at 36°F or colder, cold enough for frost on exposed plants.
- Tonight 35°F Frost possible · Mostly Clear
- Fri, Nov 6 39°F Above 36°F · Slight Chance Rain Showers then Mostly Cloudy
- Sat, Nov 7 40°F Above 36°F · Mostly Cloudy
- Sun, Nov 8 36°F Frost possible · Mostly Cloudy
- Mon, Nov 9 38°F Above 36°F · Partly Cloudy then Slight Chance Rain Showers
- Tue, Nov 10 42°F Above 36°F · Slight Chance Rain Showers
- Wed, Nov 11 41°F Above 36°F · Slight Chance Rain Showers then 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 Umatilla
The median first fall hard-freeze date (28°F) is November 14, from NOAA’s 1991–2020 Climate Normals at Mcnary Dam #2. 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 2 · Apr 20 · May 7 | Oct 9 · Oct 24 · Nov 6 | 185 days |
| 32°F freeze | Mar 12 · Mar 30 · Apr 20 | Oct 21 · Nov 4 · Nov 19 | 217 days |
| 28°F hard freeze | Feb 19 · Mar 11 · Mar 30 | Oct 28 · Nov 14 · Dec 3 | 247 days |
Average high temperature by month
1991–2020 normals at Mcnary Dam #2
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 Umatilla, OR come from the nearest weather station with freeze statistics in NOAA’s 1991–2020 Climate Normals: Mcnary Dam #2 (station USC00355392, elevation 361 ft), 2.0 mi from Umatilla. 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 Umatilla
| City | Distance | Last spring frost | First fall frost |
|---|---|---|---|
| Hermiston, OR | 6.2 mi | Apr 26 | Oct 10 |
| Kennewick, WA | 21 mi | Mar 28 | Oct 30 |
| Richland, WA | 25 mi | Apr 6 | Oct 24 |
| Pasco, WA | 26 mi | Apr 27 | Oct 11 |
| West Richland, WA | 27 mi | Apr 6 | Oct 24 |
| Prosser, WA | 29 mi | Apr 14 | Oct 22 |
| Pendleton, OR | 30 mi | Apr 22 | Oct 9 |
| Grandview, WA | 35 mi | May 1 | Oct 6 |
| Sunnyside, WA | 42 mi | May 1 | Oct 6 |
| Milton-Freewater, OR | 45 mi | Mar 25 | Oct 29 |
Frequently asked questions
When is the last frost in Umatilla?
On average, the last spring frost (32°F) in Umatilla is around March 30. In about 1 year in 10 it comes after April 20, and in 9 years in 10 it comes after March 12.
When is the first frost in Umatilla?
The first fall frost (32°F) usually arrives around November 4. There’s a 10% chance of a freeze by October 21 and a 90% chance by November 19.
Can it frost in Umatilla 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 April 20.
What growing zone is Umatilla?
Umatilla is in USDA Plant Hardiness Zone 7b (average annual extreme minimum temperature 5 to 10°F), based on the 2023 USDA map for ZIP code 97882. See growing zones in Oregon.
More: all Oregon frost dates · Oregon growing zones · frost vs. freeze