Frost history / Concord Wwtp, CA
Concord Wwtp, CA: frost dates by year
Last spring and first fall frost at NOAA station USC00041967, 1992 to 2018, measured from daily minimum temperatures.
Elevation 40 ft, 37.983, -122.069. Download the data (JSON), NOAA daily records
Summary at 32°F
| Last spring frost | First fall frost | |
|---|---|---|
| Median | Jan 18 | Dec 18 |
| Earliest | Jan 3 (2015) | Nov 11 (2000) |
| Latest | Feb 26 (2011) | Dec 31 (2014) |
| Trend | 4.1 days later per decade | 2.3 days later per decade |
| Years with data | 25, 9 with no freeze | 26, 7 with no freeze |
At 28°F (hard freeze) the median last spring date is Jan 13 and the median first fall date is Dec 15.
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 | Feb 20 | none | none | none |
| 2017 | Jan 6 | Dec 23 | none | none |
| 2016 | none | Dec 17 | none | none |
| 2015 | Jan 3 | Nov 29 | none | none |
| 2014 | none | Dec 31 | none | none |
| 2013 | Jan 20 | Dec 5 | Jan 13 | Dec 5 |
| 2012 | Jan 17 | no data | none | no data |
| 2011 | Feb 26 | Dec 18 | none | Dec 24 |
| 2010 | none | Nov 25 | none | none |
| 2009 | Jan 18 | Dec 8 | none | Dec 9 |
| 2008 | none | Dec 20 | none | none |
| 2007 | Jan 24 | Dec 22 | Jan 16 | none |
| 2006 | none | Dec 18 | none | none |
| 2005 | none | none | none | none |
| 2004 | Jan 5 | Nov 30 | none | none |
| 2003 | Feb 9 | Dec 27 | none | none |
| 2002 | Jan 31 | none | none | none |
| 2001 | Jan 18 | none | none | none |
| 2000 | no data | Nov 11 | no data | none |
| 1999 | Jan 24 | none | none | none |
| 1998 | no data | Dec 21 | no data | Dec 21 |
| 1997 | Jan 14 | Dec 12 | none | none |
| 1996 | none | none | none | none |
| 1995 | none | none | none | none |
| 1994 | none | Nov 19 | none | none |
| 1993 | Jan 11 | Dec 23 | Jan 4 | none |
| 1992 | Jan 13 | Dec 18 | none | none |
"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.