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Frost Dates in Utah
First and last frost dates across Utah, computed from 88 NOAA weather stations (1991–2020 climate normals). Your exact date depends on your city and microclimate — use the ZIP lookup on the main tool for a station-specific answer.
Last spring frost
May 13
statewide median · range Mar 9–Jun 17
First fall frost
Oct 4
statewide median · range Sep 1–Nov 20
Growing season
143 days
median · range 76–253
Stations used
88
NOAA 1991–2020 normals
Frost dates by city
Median dates from the nearest NOAA station to each city. The "cautious" date is the 10% spring value — planting after it means only a ~10% chance of a later frost.
| City | Nearest station | Last spring frost | First fall frost | Growing season | Safe transplant |
|---|---|---|---|---|---|
| Salt Lake City | Salt Lake City Intl Ap · 4 mi | Apr 8 (cautious: Apr 30) | Oct 31 | 204 days | Apr 22 |
| Provo | Provo Byu · 1 mi | Apr 18 (cautious: May 5) | Oct 21 | 185 days | May 2 |
| Ogden | Ogden Hinkley Ap · 3 mi | Apr 22 (cautious: May 10) | Oct 22 | 180 days | May 6 |
How frost varies across Utah
Spring frost timing spans about 100 days across the state. Hite Rs in southeastern Utah typically sees its last spring frost around March 9, while Angle in southern Utah doesn't clear frost until about June 17. Within any city, low spots and valleys run colder than the station average; areas near buildings and pavement run warmer.
When to plant in Utah
As a rule of thumb, cool-season crops (lettuce, peas, spinach) can go in 2–4 weeks before your last spring frost; warm-season transplants (tomatoes, peppers) should wait about 2 weeks after it — around May 27 for the statewide median. Check your city's row above rather than the statewide median: a 100-day statewide spread makes the city-level date the one that matters.
These are climate normals (what's typical), not forecasts. For the current year, watch the 10-day forecast around your planting date.
How this is computed
Statewide medians are the median of the 88 NOAA stations' median frost dates — half the stations run earlier, half later. City rows use the nearest station with 30-year freeze records. Dates are 32°F freeze probabilities from NOAA NCEI 1991–2020 U.S. Climate Normals; nothing is estimated or interpolated.
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Frequently asked questions
When is the last frost date in Utah?
The statewide median last spring frost is May 13, but it ranges from March 9 to June 17 depending on where in the state you are. Use your city's row in the table above, or the ZIP lookup on the main tool, for a station-specific date.
When can I plant tomatoes outside in Utah?
Warm-season transplants like tomatoes should wait about two weeks after your last spring frost — around May 27 for the statewide median. Your city may differ by weeks; check the "safe transplant" column in the city table.
How long is the growing season in Utah?
The median growing season across 88 NOAA stations is 143 days, ranging from 76 to 253 days by location.
Why do frost dates vary so much within Utah?
Frost timing follows latitude, elevation, and local terrain. Across Utah, last spring frost dates span about 100 days — from around March 9 near Hite Rs to June 17 near Angle. Microclimates (low spots, valleys, urban heat) shift dates further at the garden level.
Where does this data come from?
All frost dates are computed from the NOAA National Centers for Environmental Information 1991–2020 U.S. Climate Normals freeze data (public domain), using each station's 32°F freeze probability statistics. No dates are estimated or interpolated.