Last spring frost
May 31
Frost Dates for Grass Valley, NV
First fall frost
Sep 17
Growing season
108 days
Hardiness zone
6b
In an average year around Grass Valley, NV, the last spring frost (32°F) is about May 31 and the first fall frost is about Sep 17, giving roughly a 108-day growing season. To be safe most years, wait until May 10 before setting out tender plants.
Last spring frost
Dates the last frost of spring typically ends. Plant tender crops after the risk has passed for your comfort level.
| Frost intensity | Early (10%) | Average (50%) | Late (90%) |
|---|---|---|---|
| Light (36°F) | Jun 30 | Jun 12 | May 29 |
| Freeze (32°F) | Jun 19 | May 31 | May 10 |
| Hard (28°F) | Jun 8 | May 13 | Apr 25 |
| Severe (24°F) | May 18 | Apr 29 | Apr 11 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Jun 30 | Jun 24 | Jun 19 | Jun 16 | Jun 12 | Jun 9 | Jun 6 | Jun 2 | May 29 |
| 32°F | Jun 19 | Jun 12 | Jun 7 | Jun 4 | May 31 | May 27 | May 22 | May 16 | May 10 |
| 28°F | Jun 8 | May 30 | May 22 | May 17 | May 13 | May 9 | May 5 | May 1 | Apr 25 |
| 24°F | May 18 | May 12 | May 6 | May 2 | Apr 29 | Apr 26 | Apr 21 | Apr 17 | Apr 11 |
| 20°F | May 5 | Apr 27 | Apr 21 | Apr 16 | Apr 12 | Apr 8 | Apr 4 | Mar 31 | Mar 24 |
| 16°F | Apr 17 | Apr 8 | Apr 4 | Mar 31 | Mar 27 | Mar 21 | Mar 15 | Mar 7 | Feb 24 |
First fall frost
Dates the first frost of fall typically arrives. Count back by a crop's days-to-maturity to know your planting cutoff.
| Frost intensity | Early (10%) | Average (50%) | Late (90%) |
|---|---|---|---|
| Light (36°F) | Aug 22 | Sep 5 | Sep 19 |
| Freeze (32°F) | Sep 3 | Sep 17 | Oct 1 |
| Hard (28°F) | Sep 15 | Sep 29 | Oct 12 |
| Severe (24°F) | Sep 26 | Oct 10 | Oct 25 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Aug 22 | Aug 28 | Aug 31 | Sep 3 | Sep 5 | Sep 8 | Sep 11 | Sep 14 | Sep 19 |
| 32°F | Sep 3 | Sep 9 | Sep 12 | Sep 15 | Sep 17 | Sep 20 | Sep 23 | Sep 27 | Oct 1 |
| 28°F | Sep 15 | Sep 20 | Sep 24 | Sep 26 | Sep 29 | Oct 1 | Oct 4 | Oct 7 | Oct 12 |
| 24°F | Sep 26 | Oct 1 | Oct 3 | Oct 7 | Oct 10 | Oct 13 | Oct 16 | Oct 20 | Oct 25 |
| 20°F | Oct 6 | Oct 11 | Oct 15 | Oct 18 | Oct 21 | Oct 24 | Oct 28 | Nov 1 | Nov 5 |
| 16°F | Oct 16 | Oct 20 | Oct 24 | Oct 28 | Oct 31 | Nov 3 | Nov 7 | Nov 12 | Nov 20 |
Growing season is measured at 32°F with about 50% probability. Hardiness zone from the 2023 USDA map; frost normals from NOAA 1991-2020.
Where this data comes from
@endif These dates are computed from the nearest official weather station with long-term records: Winnemucca Muni Ap, Nv, about 7.7 miles away@if(!empty($station['elevation_ft'])), at 4,296 ft elevation. The further the station and the greater the elevation difference from your yard, the more your local frost timing can vary.
How we calculate these dates
Frost and freeze dates come from the NOAA 1991–2020 U.S. Climate Normals, the National Oceanic and Atmospheric Administration's 30-year averages for each weather station. A date shown at the 50% level is the median: in half of years the frost falls on or before it. The 10% and 90% columns show the early and late ends of the range, so you can plant on the odds you're comfortable with. These are long-term averages, not a forecast for this year - always check your local outlook before planting.
Source: NOAA National Centers for Environmental Information, 1991–2020 Climate Normals (public domain). Harman is not affiliated with or endorsed by NOAA.
Frequently asked questions
When is the last frost in Grass Valley, NV?
On average, the last spring frost (32°F) around Grass Valley, NV is about May 31. In cooler years it can run later, so for a safer bet many gardeners wait until May 10.
When is the first frost in the fall?
The first fall frost around Grass Valley, NV typically arrives about Sep 17. Count back by a crop's days to maturity to find the latest date you can plant it.
When can I plant tomatoes and other tender crops?
Tender crops like tomatoes, peppers and basil are damaged by frost, so wait until the last spring frost has passed - around May 31 on average, or May 10 to be safe most years.
How long is the growing season here?
The frost-free growing season (between the last spring and first fall 32°F frost) is about 108 days in a typical year.
Are these dates a forecast for this year?
No. They are 30-year averages from the NOAA 1991–2020 Climate Normals, not a prediction for the current year. Use them for planning and always check your local weather forecast before planting or protecting crops.
Local weather for 89446 Planting calendar → Nevada frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026