Frost history / Copper Harbor, MI
Copper Harbor, MI: frost dates by year
Last spring and first fall frost at NOAA station USW00094899, 1998 to 2024, measured from daily minimum temperatures.
Elevation 626 ft, 47.467, -87.883. Download the data (JSON), NOAA daily records
Summary at 32°F
| Last spring frost | First fall frost | |
|---|---|---|
| Median | May 6 | Oct 21 |
| Earliest | Apr 22 (2010) | Sep 27 (2000) |
| Latest | May 28 (2021) | Nov 10 (2021) |
| Trend | 1.5 days later per decade | 7.5 days later per decade |
| Years with data | 25 | 27 |
At 28°F (hard freeze) the median last spring date is Apr 20 and the median first fall date is Nov 14.
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 |
|---|---|---|---|---|
| 2024 | Apr 25 | Nov 1 | Apr 7 | Nov 30 |
| 2023 | Apr 24 | Oct 30 | Apr 8 | Nov 24 |
| 2022 | May 6 | Oct 27 | Apr 28 | Nov 14 |
| 2021 | May 28 | Nov 10 | Apr 20 | Nov 21 |
| 2020 | May 12 | Oct 16 | May 8 | Nov 13 |
| 2019 | May 8 | Oct 17 | Apr 28 | Nov 5 |
| 2018 | May 12 | Oct 13 | Apr 29 | Nov 8 |
| 2017 | May 19 | Oct 31 | Apr 17 | Nov 8 |
| 2016 | May 5 | Oct 21 | Apr 12 | Nov 19 |
| 2015 | May 22 | Oct 22 | Apr 25 | Nov 21 |
| 2014 | no data | Oct 18 | no data | Nov 7 |
| 2013 | May 24 | Oct 28 | Apr 24 | Oct 28 |
| 2012 | Apr 29 | Oct 27 | Apr 29 | Nov 12 |
| 2011 | May 27 | Oct 27 | Apr 19 | Nov 17 |
| 2010 | Apr 22 | Oct 31 | Apr 22 | Nov 18 |
| 2009 | Apr 29 | Oct 10 | Apr 15 | Dec 3 |
| 2008 | May 4 | Oct 21 | Apr 14 | Nov 16 |
| 2007 | Apr 25 | Oct 24 | Apr 15 | Nov 16 |
| 2006 | May 6 | Oct 12 | Apr 7 | Nov 3 |
| 2005 | May 12 | Oct 20 | Apr 4 | Nov 16 |
| 2004 | May 7 | Oct 18 | Apr 24 | Nov 9 |
| 2003 | May 2 | Oct 5 | Apr 26 | Oct 27 |
| 2002 | May 19 | Oct 13 | Apr 23 | Oct 14 |
| 2001 | Apr 28 | Oct 27 | Apr 16 | Oct 30 |
| 2000 | May 19 | Sep 27 | Apr 15 | Nov 17 |
| 1999 | Apr 24 | Oct 3 | Apr 24 | Nov 16 |
| 1998 | no data | Oct 15 | no data | Nov 12 |
"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.