Last Frost Day

Frost history / Ames 5 Se, IA

Ames 5 Se, IA: frost dates by year

Last spring and first fall frost at NOAA station USC00130203, 1996 to 2025, measured from daily minimum temperatures.

Elevation 870 ft, 41.952, -93.566. Download the data (JSON), NOAA daily records

Summary at 32°F

Last spring frostFirst fall frost
MedianApr 23Oct 11
EarliestApr 5 (1998)Sep 23 (2012)
LatestMay 12 (2013)Oct 28 (2017)
Trend0.9 days later per decade3.1 days later per decade
Years with data2828

At 28°F (hard freeze) the median last spring date is Apr 16 and the median first fall date is Oct 24.

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)

Mar 31Apr 15Apr 30May 15May 302000201020201996: Apr 281998: Apr 51999: Apr 192001: Apr 192002: Apr 92003: Apr 122004: May 42005: May 52006: May 72007: Apr 142008: Apr 302009: Apr 162010: May 102011: May 52012: Apr 132013: May 122014: Apr 192015: Apr 242016: Apr 132017: Apr 82018: Apr 212019: Apr 292020: May 102021: Apr 252022: Apr 272023: Apr 262024: Apr 222025: Apr 7

First fall frost (32°F)

Sep 12Sep 27Oct 12Oct 27Nov 112000201020201996: Oct 41998: Oct 221999: Oct 42001: Oct 62002: Oct 72003: Sep 292004: Oct 22005: Oct 82006: Oct 122007: Oct 232008: Oct 282009: Oct 102010: Oct 192011: Oct 22012: Sep 232013: Oct 222014: Oct 52015: Oct 172016: Oct 132017: Oct 282018: Oct 152019: Oct 122020: Oct 22021: Oct 222022: Oct 82023: Oct 102024: Oct 162025: Oct 25

Dots are single years. The gray line is the median, the green line the fitted trend.

Year by year

YearLast spring 32°FFirst fall 32°FLast spring 28°FFirst fall 28°F
2025Apr 7Oct 25Apr 7Nov 9
2024Apr 22Oct 16Apr 6Oct 16
2023Apr 26Oct 10Apr 25Oct 28
2022Apr 27Oct 8Apr 27Oct 8
2021Apr 25Oct 22Apr 23Oct 24
2020May 10Oct 2Apr 17Oct 24
2019Apr 29Oct 12Apr 29Oct 12
2018Apr 21Oct 15Apr 21Oct 21
2017Apr 8Oct 28Apr 8Oct 29
2016Apr 13Oct 13Apr 13Oct 14
2015Apr 24Oct 17Apr 4Nov 20
2014Apr 19Oct 5Apr 19Oct 31
2013May 12Oct 22Apr 25Oct 25
2012Apr 13Sep 23Apr 13Oct 6
2011May 5Oct 2May 4Oct 21
2010May 10Oct 19Mar 30Oct 29
2009Apr 16Oct 10Apr 12Oct 10
2008Apr 30Oct 28Apr 30Oct 28
2007Apr 14Oct 23Apr 14Oct 29
2006May 7Oct 12Apr 9Oct 13
2005May 5Oct 8May 5Oct 27
2004May 4Oct 2May 3Nov 3
2003Apr 12Sep 29Apr 9Oct 1
2002Apr 9Oct 7Apr 7Oct 14
2001Apr 19Oct 6Apr 19Oct 16
1999Apr 19Oct 4Mar 27Oct 4
1998Apr 5Oct 22Mar 24Nov 5
1996Apr 28Oct 4Apr 23Oct 31

"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.