Frost history / Duluth Nws, MN
Duluth Nws, MN: frost dates by year
Last spring and first fall frost at NOAA station USC00212250, 2012 to 2025, measured from daily minimum temperatures.
Elevation 1,433 ft, 46.837, -92.211. Download the data (JSON), NOAA daily records
Summary at 32°F
| Last spring frost | First fall frost | |
|---|---|---|
| Median | May 15 | Oct 8 |
| Earliest | Apr 30 (2012) | Sep 18 (2020) |
| Latest | May 30 (2021) | Oct 22 (2021) |
| Trend | 3.2 days earlier per decade | 5.3 days later per decade |
| Years with data | 13 | 12 |
At 28°F (hard freeze) the median last spring date is Apr 30 and the median first fall date is Oct 17.
The trend is a straight-line fit through the years with a freeze. A positive spring trend means the last frost now comes later. Short or patchy records give noisy trends.
Chart
Last spring frost (32°F)
First fall frost (32°F)
Dots are single years. The gray line is the median, the green line the fitted trend.
Year by year
| Year | Last spring 32°F | First fall 32°F | Last spring 28°F | First fall 28°F |
|---|---|---|---|---|
| 2025 | May 19 | Oct 8 | Apr 30 | Oct 23 |
| 2024 | Apr 30 | Oct 14 | Apr 26 | Oct 31 |
| 2023 | May 4 | Oct 10 | May 1 | Oct 18 |
| 2022 | May 5 | Sep 28 | Apr 29 | Oct 8 |
| 2021 | May 30 | Oct 22 | May 12 | Oct 23 |
| 2020 | May 12 | Sep 18 | May 12 | Oct 4 |
| 2019 | May 21 | Oct 12 | May 8 | Oct 26 |
| 2018 | May 21 | Sep 30 | May 13 | Oct 12 |
| 2017 | May 9 | no data | Apr 29 | no data |
| 2015 | May 20 | Oct 8 | Apr 28 | Oct 17 |
| 2014 | May 15 | Oct 7 | Apr 27 | Oct 11 |
| 2013 | May 25 | Oct 15 | May 13 | Oct 21 |
| 2012 | Apr 30 | Sep 19 | Apr 28 | Oct 8 |
"none" means the station recorded no freeze at that threshold in that half of the year. "no data" means more than 10% of the season's daily readings were missing. Years with no usable data are left out. See the methodology for the rules, and the ZIP lookup for 1991 to 2020 frost probabilities.