Last spring frost
May 16
Frost Dates for Deer River, MN
First fall frost
Oct 1
Growing season
138 days
Hardiness zone
3b
In an average year around Deer River, MN, the last spring frost (32°F) is about May 16 and the first fall frost is about Oct 1, giving roughly a 138-day growing season. To be safe most years, wait until May 1 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 9 | May 27 | May 15 |
| Freeze (32°F) | May 31 | May 16 | May 1 |
| Hard (28°F) | May 19 | May 3 | Apr 21 |
| Severe (24°F) | May 6 | Apr 23 | Apr 9 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Jun 9 | Jun 4 | Jun 2 | May 30 | May 27 | May 24 | May 22 | May 19 | May 15 |
| 32°F | May 31 | May 26 | May 23 | May 19 | May 16 | May 13 | May 10 | May 5 | May 1 |
| 28°F | May 19 | May 14 | May 10 | May 6 | May 3 | May 1 | Apr 28 | Apr 25 | Apr 21 |
| 24°F | May 6 | May 1 | Apr 29 | Apr 25 | Apr 23 | Apr 21 | Apr 18 | Apr 14 | Apr 9 |
| 20°F | Apr 26 | Apr 22 | Apr 19 | Apr 16 | Apr 13 | Apr 10 | Apr 8 | Apr 5 | Apr 1 |
| 16°F | Apr 19 | Apr 14 | Apr 10 | Apr 7 | Apr 5 | Apr 3 | Apr 1 | Mar 28 | Mar 22 |
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) | Sep 6 | Sep 22 | Oct 3 |
| Freeze (32°F) | Sep 18 | Oct 1 | Oct 12 |
| Hard (28°F) | Sep 27 | Oct 10 | Oct 25 |
| Severe (24°F) | Oct 8 | Oct 22 | Nov 5 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 6 | Sep 13 | Sep 17 | Sep 19 | Sep 22 | Sep 24 | Sep 26 | Sep 29 | Oct 3 |
| 32°F | Sep 18 | Sep 23 | Sep 26 | Sep 28 | Oct 1 | Oct 3 | Oct 5 | Oct 9 | Oct 12 |
| 28°F | Sep 27 | Oct 1 | Oct 5 | Oct 7 | Oct 10 | Oct 13 | Oct 16 | Oct 20 | Oct 25 |
| 24°F | Oct 8 | Oct 13 | Oct 16 | Oct 19 | Oct 22 | Oct 25 | Oct 28 | Nov 1 | Nov 5 |
| 20°F | Oct 17 | Oct 24 | Oct 28 | Oct 31 | Nov 1 | Nov 4 | Nov 7 | Nov 11 | Nov 16 |
| 16°F | Oct 30 | Nov 1 | Nov 4 | Nov 7 | Nov 9 | Nov 12 | Nov 15 | Nov 19 | Nov 23 |
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: Pokegama Dam, Mn, about 15.6 miles away@if(!empty($station['elevation_ft'])), at 1,280 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 Deer River, MN?
On average, the last spring frost (32°F) around Deer River, MN is about May 16. In cooler years it can run later, so for a safer bet many gardeners wait until May 1.
When is the first frost in the fall?
The first fall frost around Deer River, MN typically arrives about Oct 1. 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 16 on average, or May 1 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 138 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 56636 Planting calendar → Minnesota frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026