Frost history / Groton, CT
Groton, CT: frost dates by year
Last spring and first fall frost at NOAA station USC00063207, 1957 to 2024, measured from daily minimum temperatures.
Elevation 40 ft, 41.350, -72.038. Download the data (JSON), NOAA daily records
Summary at 32°F
| Last spring frost | First fall frost | |
|---|---|---|
| Median | Apr 18 | Oct 21 |
| Earliest | Mar 24 (2024) | Sep 24 (1963) |
| Latest | May 11 (1966) | Nov 14 (2014) |
| Trend | 4.0 days earlier per decade | 2.9 days later per decade |
| Years with data | 50 | 53 |
At 28°F (hard freeze) the median last spring date is Apr 6 and the median first fall date is Nov 6.
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 | Mar 24 | Nov 4 | Mar 23 | Dec 1 |
| 2023 | no data | Nov 2 | no data | Nov 13 |
| 2020 | Apr 23 | no data | Mar 16 | no data |
| 2017 | Mar 30 | no data | Mar 24 | no data |
| 2015 | no data | Oct 19 | no data | Oct 19 |
| 2014 | no data | Nov 14 | no data | Nov 15 |
| 2013 | no data | Oct 26 | no data | Nov 13 |
| 2011 | Apr 8 | Oct 31 | Mar 28 | Dec 11 |
| 2008 | Apr 3 | Oct 24 | Apr 3 | Nov 19 |
| 2007 | Apr 11 | no data | Apr 7 | no data |
| 2004 | Apr 6 | Nov 4 | Mar 23 | Nov 10 |
| 2003 | Apr 18 | Oct 25 | Mar 16 | Nov 9 |
| 2002 | Apr 7 | Oct 24 | Mar 23 | Nov 27 |
| 2001 | no data | Oct 29 | no data | Nov 12 |
| 2000 | Apr 15 | Sep 30 | Mar 19 | Nov 23 |
| 1999 | Apr 11 | Oct 15 | Apr 11 | Nov 8 |
| 1998 | Apr 12 | no data | Mar 25 | no data |
| 1997 | Apr 15 | Oct 23 | Apr 10 | Oct 23 |
| 1996 | Apr 12 | Nov 2 | Apr 9 | Nov 12 |
| 1995 | Apr 17 | Nov 5 | Apr 6 | Nov 6 |
| 1994 | Apr 9 | Nov 12 | Mar 31 | Nov 23 |
| 1993 | Apr 8 | Oct 11 | Mar 24 | Oct 11 |
| 1992 | no data | Oct 1 | no data | Nov 2 |
| 1991 | Apr 19 | Oct 21 | Mar 31 | Nov 6 |
| 1990 | Apr 19 | Oct 28 | Apr 13 | Nov 9 |
| 1989 | no data | Nov 4 | no data | Nov 19 |
| 1988 | Apr 23 | no data | Mar 23 | no data |
| 1987 | Apr 2 | Oct 26 | Apr 2 | Nov 12 |
| 1986 | Apr 13 | Oct 11 | Mar 25 | Nov 13 |
| 1985 | Apr 12 | Oct 29 | Apr 10 | Nov 16 |
| 1984 | Apr 22 | Oct 6 | Apr 2 | Oct 6 |
| 1983 | Apr 2 | Oct 21 | Apr 2 | Oct 30 |
| 1982 | Apr 23 | Oct 18 | Apr 23 | Nov 11 |
| 1981 | Apr 22 | Oct 11 | Apr 16 | Nov 12 |
| 1980 | Apr 18 | Oct 10 | Mar 17 | Oct 31 |
| 1979 | Apr 22 | Oct 10 | Apr 21 | Nov 16 |
| 1978 | Apr 24 | Oct 9 | Apr 3 | Oct 17 |
| 1977 | Apr 11 | Oct 24 | Apr 10 | Nov 14 |
| 1976 | Apr 13 | Oct 11 | Apr 12 | Oct 19 |
| 1975 | Apr 23 | Oct 31 | Apr 10 | Nov 1 |
| 1974 | May 8 | Oct 5 | Apr 10 | Oct 19 |
| 1973 | Apr 21 | Oct 18 | Apr 14 | Nov 6 |
| 1972 | Apr 28 | Oct 10 | Apr 28 | Oct 20 |
| 1971 | Apr 25 | Nov 6 | Apr 9 | Nov 8 |
| 1970 | May 7 | Oct 20 | Apr 11 | Oct 28 |
| 1969 | Apr 21 | Oct 23 | Apr 3 | Oct 24 |
| 1968 | Apr 12 | Oct 31 | Mar 26 | Nov 1 |
| 1967 | May 7 | Oct 30 | Apr 13 | Nov 6 |
| 1966 | May 11 | Oct 27 | Apr 15 | Oct 30 |
| 1965 | Apr 21 | Oct 5 | Apr 5 | Oct 6 |
| 1964 | May 4 | Oct 12 | Apr 6 | Oct 12 |
| 1963 | Apr 29 | Sep 24 | Apr 14 | Nov 25 |
| 1962 | Apr 21 | Oct 25 | Apr 18 | Oct 25 |
| 1961 | May 3 | Oct 16 | Apr 20 | Oct 28 |
| 1960 | Apr 20 | Oct 21 | Apr 11 | Oct 22 |
| 1959 | Apr 23 | Oct 16 | Apr 14 | Oct 20 |
| 1958 | Apr 14 | Oct 6 | Apr 10 | Nov 8 |
| 1957 | no data | Sep 27 | no data | 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.