Frost history / Thief Rvr Falls 2, MN
Thief Rvr Falls 2, MN: frost dates by year
Last spring and first fall frost at NOAA station USC00218247, 1973 to 2004, measured from daily minimum temperatures.
Elevation 1,128 ft, 48.133, -96.182. Download the data (JSON), NOAA daily records
Summary at 32°F
| Last spring frost | First fall frost | |
|---|---|---|
| Median | May 17 | Sep 22 |
| Earliest | Apr 23 (1987) | Aug 20 (2004) |
| Latest | Jun 3 (1996) | Oct 24 (1994) |
| Trend | 0.8 days later per decade | 3.8 days earlier per decade |
| Years with data | 22 | 17 |
At 28°F (hard freeze) the median last spring date is May 8 and the median first fall date is Sep 29.
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 |
|---|---|---|---|---|
| 2004 | May 14 | Aug 20 | May 4 | Oct 4 |
| 2003 | May 20 | Sep 25 | Apr 29 | Sep 28 |
| 2002 | no data | Sep 21 | no data | Sep 21 |
| 1999 | May 9 | Sep 20 | Apr 23 | Oct 2 |
| 1996 | Jun 3 | no data | May 11 | no data |
| 1995 | May 24 | no data | Apr 26 | no data |
| 1994 | May 12 | Oct 24 | May 6 | Oct 25 |
| 1993 | no data | Sep 10 | no data | Sep 29 |
| 1992 | May 24 | no data | May 3 | no data |
| 1991 | May 3 | Sep 20 | May 2 | Sep 26 |
| 1990 | May 20 | Oct 6 | May 18 | Oct 7 |
| 1989 | no data | Sep 11 | no data | Sep 23 |
| 1988 | May 16 | no data | May 13 | no data |
| 1987 | Apr 23 | no data | Apr 23 | no data |
| 1986 | May 18 | Sep 13 | May 18 | Sep 13 |
| 1984 | May 26 | no data | May 9 | no data |
| 1983 | May 25 | Sep 22 | May 25 | Oct 12 |
| 1982 | Jun 2 | no data | May 8 | no data |
| 1981 | May 30 | Sep 28 | May 10 | Sep 28 |
| 1980 | May 15 | Sep 23 | May 15 | Sep 27 |
| 1979 | May 19 | Oct 5 | May 15 | Oct 9 |
| 1978 | May 1 | Sep 27 | Apr 22 | Oct 7 |
| 1977 | May 7 | Oct 2 | May 7 | Oct 15 |
| 1974 | May 15 | no data | May 6 | no data |
| 1973 | May 16 | Sep 15 | May 16 | Sep 16 |
"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.