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Will it freeze in Union Gap in the next 7 nights?
The earliest overnight low at or below 32°F in the available NWS frost forecast is Tonight: 32°F (Thu, Nov 5, 6:00 PM PST to Fri, Nov 6, 6:00 AM PST).
Tonight: forecast low 32°F. Freeze.
NWS forecast period: Thu, Nov 5, 6:00 PM PST to Fri, Nov 6, 6:00 AM PST.
4 of the next 7 nights are forecast at 36°F or colder, cold enough for frost on exposed plants.
- Tonight 32°F Freeze · Partly Cloudy then Patchy Fog
- Fri, Nov 6 36°F Frost possible · Chance Rain Showers then Areas Of Fog
- Sat, Nov 7 37°F Above 36°F · Slight Chance Rain Showers
- Sun, Nov 8 31°F Freeze · Mostly Cloudy
- Mon, Nov 9 34°F Frost possible · Chance Rain Showers
- Tue, Nov 10 38°F Above 36°F · Chance Rain Showers
- Wed, Nov 11 38°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 Union Gap
The median first fall hard-freeze date (28°F) is October 16, from NOAA’s 1991–2020 Climate Normals at Yakima Air Terminal. 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 9 · May 29 · Jun 16 | Sep 8 · Sep 23 · Oct 5 | 117 days |
| 32°F freeze | Apr 24 · May 8 · May 27 | Sep 23 · Oct 4 · Oct 17 | 149 days |
| 28°F hard freeze | Apr 6 · Apr 23 · May 8 | Oct 2 · Oct 16 · Nov 1 | 175 days |
Average high temperature by month
1991–2020 normals at Yakima Air Terminal
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 Union Gap, WA come from the nearest weather station with freeze statistics in NOAA’s 1991–2020 Climate Normals: Yakima Air Terminal (station USW00024243, elevation 1,064 ft), 2.6 mi from Union Gap. 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 Union Gap
| City | Distance | Last spring frost | First fall frost |
|---|---|---|---|
| Yakima, WA | 3.7 mi | Apr 8 | Oct 23 |
| Selah, WA | 6.8 mi | May 5 | Oct 4 |
| Toppenish, WA | 15 mi | Apr 21 | Oct 15 |
| Sunnyside, WA | 29 mi | May 1 | Oct 6 |
| Ellensburg, WA | 31 mi | May 8 | Oct 2 |
| Grandview, WA | 35 mi | May 1 | Oct 6 |
| Prosser, WA | 42 mi | Apr 14 | Oct 22 |
| West Richland, WA | 55 mi | Apr 6 | Oct 24 |
| Quincy, WA | 56 mi | Apr 21 | Oct 16 |
| Richland, WA | 60 mi | Apr 6 | Oct 24 |
Frequently asked questions
When is the last frost in Union Gap?
On average, the last spring frost (32°F) in Union Gap is around May 8. In about 1 year in 10 it comes after May 27, and in 9 years in 10 it comes after April 24.
When is the first frost in Union Gap?
The first fall frost (32°F) usually arrives around October 4. There’s a 10% chance of a freeze by September 23 and a 90% chance by October 17.
Can it frost in Union Gap 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 29.
What growing zone is Union Gap?
Union Gap 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 98902. See growing zones in Washington.
More: all Washington frost dates · Washington growing zones · frost vs. freeze