Frost history / Copper Harbor Ft Wilkins, MI
Copper Harbor Ft Wilkins, MI: frost dates by year
Last spring and first fall frost at NOAA station USC00201780, 1973 to 2018, measured from daily minimum temperatures.
Elevation 625 ft, 47.468, -87.867. Download the data (JSON), NOAA daily records
Summary at 32°F
| Last spring frost | First fall frost | |
|---|---|---|
| Median | May 19 | Oct 16 |
| Earliest | Apr 28 (1998) | Aug 9 (1996) |
| Latest | Jun 21 (1992) | Nov 1 (1994) |
| Trend | 0.8 days earlier per decade | 4.9 days later per decade |
| Years with data | 21 | 21 |
At 28°F (hard freeze) the median last spring date is May 3 and the median first fall date is Oct 31.
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 |
|---|---|---|---|---|
| 2018 | May 20 | no data | May 11 | no data |
| 2017 | no data | Oct 26 | no data | Nov 1 |
| 2016 | no data | Oct 22 | no data | Nov 19 |
| 2013 | May 26 | Oct 22 | Apr 25 | Oct 29 |
| 2012 | Apr 29 | Oct 16 | Apr 29 | Oct 29 |
| 2011 | May 28 | Oct 28 | May 4 | Nov 17 |
| 2010 | May 9 | no data | Apr 22 | no data |
| 2009 | May 11 | Oct 1 | Apr 29 | Nov 6 |
| 2008 | May 27 | Oct 18 | May 4 | Nov 1 |
| 2007 | no data | Oct 25 | no data | Oct 25 |
| 2005 | May 12 | Oct 21 | May 12 | Nov 11 |
| 2004 | May 28 | no data | May 3 | no data |
| 2003 | no data | Oct 6 | no data | Oct 27 |
| 2000 | May 19 | no data | Apr 25 | no data |
| 1999 | Apr 29 | no data | Apr 24 | no data |
| 1998 | Apr 28 | Oct 15 | Apr 27 | Nov 12 |
| 1997 | May 18 | Oct 14 | May 4 | Oct 28 |
| 1996 | May 30 | Aug 9 | May 11 | Oct 31 |
| 1995 | May 22 | Oct 25 | May 22 | Nov 1 |
| 1994 | May 27 | Nov 1 | May 7 | Nov 10 |
| 1993 | May 1 | Oct 9 | Apr 26 | Nov 5 |
| 1992 | Jun 21 | Sep 23 | May 6 | Oct 30 |
| 1991 | May 20 | Sep 29 | Apr 23 | Oct 13 |
| 1990 | no data | Oct 10 | no data | Oct 10 |
| 1989 | May 13 | Oct 8 | May 6 | Oct 8 |
| 1984 | no data | Oct 28 | no data | Oct 31 |
| 1973 | May 16 | no data | Apr 29 | no data |
"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.