Frost history / Tohono Chul, AZ
Tohono Chul, AZ: frost dates by year
Last spring and first fall frost at NOAA station USC00028590, 2009 to 2025, measured from daily minimum temperatures.
Elevation 2,527 ft, 32.339, -110.981. Download the data (JSON), NOAA daily records
Summary at 32°F
| Last spring frost | First fall frost | |
|---|---|---|
| Median | Feb 24 | Dec 11 |
| Earliest | Jan 7 (2014) | Nov 26 (2010) |
| Latest | Mar 20 (2012) | Dec 24 (2014) |
| Trend | 3.6 days earlier per decade | 3.2 days later per decade |
| Years with data | 11 | 13, 3 with no freeze |
At 28°F (hard freeze) the median last spring date is Feb 5 and the median first fall date is Dec 19.
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 |
|---|---|---|---|---|
| 2025 | no data | none | no data | none |
| 2024 | Feb 11 | none | Jan 12 | none |
| 2023 | Mar 1 | none | Feb 15 | none |
| 2022 | Feb 25 | Dec 14 | Feb 6 | none |
| 2021 | no data | Dec 18 | no data | none |
| 2018 | no data | Dec 14 | no data | Dec 29 |
| 2017 | Feb 1 | Dec 8 | Jan 29 | Dec 22 |
| 2016 | Feb 6 | Nov 30 | Feb 5 | none |
| 2015 | Jan 24 | Nov 29 | Jan 5 | Dec 16 |
| 2014 | Jan 7 | Dec 24 | none | Dec 27 |
| 2013 | Mar 1 | Dec 6 | Feb 25 | Dec 6 |
| 2012 | Mar 20 | no data | none | no data |
| 2011 | Mar 1 | no data | Feb 5 | no data |
| 2010 | Feb 24 | Nov 26 | none | Nov 30 |
| 2009 | no data | Dec 24 | no data | 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.