Frost history / Ely, MN
Ely, MN: frost dates by year
Last spring and first fall frost at NOAA station USC00212543, 1998 to 2009, measured from daily minimum temperatures.
Elevation 1,382 ft, 47.924, -91.859. Download the data (JSON), NOAA daily records
Summary at 32°F
| Last spring frost | First fall frost | |
|---|---|---|
| Median | May 22 | Sep 21 |
| Earliest | May 10 (1998) | Aug 21 (2004) |
| Latest | Jun 6 (2009) | Oct 3 (2008) |
| Trend | 12.4 days later per decade | 4.8 days later per decade |
| Years with data | 12 | 12 |
At 28°F (hard freeze) the median last spring date is May 14 and the median first fall date is Oct 1.
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 |
|---|---|---|---|---|
| 2009 | Jun 6 | Sep 30 | May 16 | Sep 30 |
| 2008 | May 28 | Oct 3 | May 28 | Oct 4 |
| 2007 | May 20 | Sep 15 | Apr 27 | Oct 24 |
| 2006 | May 23 | Sep 9 | May 21 | Oct 10 |
| 2005 | May 18 | Sep 23 | May 12 | Oct 7 |
| 2004 | May 28 | Aug 21 | May 15 | Sep 29 |
| 2003 | May 31 | Sep 25 | May 3 | Sep 29 |
| 2002 | May 21 | Sep 23 | May 21 | Oct 3 |
| 2001 | May 12 | Sep 14 | May 12 | Sep 24 |
| 2000 | Jun 5 | Sep 15 | May 19 | Sep 27 |
| 1999 | May 14 | Sep 21 | Apr 25 | Sep 22 |
| 1998 | May 10 | Sep 22 | Apr 28 | Oct 21 |
"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.