Last Frost Day

Frost history / Port Washington, WI

Port Washington, WI: frost dates by year

Last spring and first fall frost at NOAA station USC00476764, 1960 to 2011, measured from daily minimum temperatures.

Elevation 594 ft, 43.394, -87.864. Download the data (JSON), NOAA daily records

Summary at 32°F

Last spring frostFirst fall frost
MedianApr 28Oct 17
EarliestApr 6 (1998)Sep 22 (1974)
LatestJun 1 (2003)Nov 19 (1985)
Trend1.4 days earlier per decade0.6 days later per decade
Years with data4750

At 28°F (hard freeze) the median last spring date is Apr 13 and the median first fall date is Oct 30.

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 30Jun 141960197019801990200020101960: Apr 181961: May 271962: Apr 211963: May 11964: Apr 91965: Apr 281966: May 131967: May 121968: Apr 291969: Apr 301970: Apr 131971: May 31972: May 71973: Apr 141974: May 71975: May 131976: May 61977: May 91978: Apr 221979: May 91980: May 91981: May 21983: May 171984: Apr 191988: Apr 281989: Apr 201990: Apr 191991: Apr 121992: Apr 281993: Apr 271994: Apr 301995: Apr 241996: Apr 281997: Apr 181998: Apr 61999: Apr 252000: Apr 202002: May 212003: Jun 12004: May 32005: Apr 292006: Apr 92007: Apr 162008: May 12009: Apr 152010: Apr 282011: Apr 21

First fall frost (32°F)

Sep 12Sep 27Oct 12Oct 27Nov 11Nov 261960197019801990200020101960: Oct 201961: Oct 261962: Oct 231963: Nov 21964: Sep 281965: Oct 251966: Oct 201967: Oct 91968: Oct 51969: Oct 151970: Oct 161971: Nov 41972: Oct 151973: Nov 31974: Sep 221975: Oct 291976: Sep 221977: Oct 161978: Oct 171979: Oct 131980: Oct 51981: Oct 181982: Sep 261983: Oct 301985: Nov 191986: Oct 181987: Oct 71988: Oct 41989: Nov 21990: Oct 191991: Oct 151993: Sep 301994: Oct 271995: Sep 231996: Oct 101997: Oct 221998: Nov 41999: Oct 242000: Oct 62001: Oct 72002: Oct 162003: Oct 22004: Oct 52005: Oct 282006: Oct 122007: Nov 72008: Oct 282009: Oct 112010: Oct 292011: Nov 10

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
2011Apr 21Nov 10Apr 18Nov 11
2010Apr 28Oct 29Apr 9Nov 18
2009Apr 15Oct 11Apr 12Oct 11
2008May 1Oct 28Apr 5Nov 10
2007Apr 16Nov 7Apr 13Nov 7
2006Apr 9Oct 12Apr 9Nov 1
2005Apr 29Oct 28Mar 27Nov 17
2004May 3Oct 5May 3Nov 12
2003Jun 1Oct 2Apr 24Nov 7
2002May 21Oct 16Apr 22Nov 1
2001no dataOct 7no dataOct 7
2000Apr 20Oct 6Apr 20Nov 14
1999Apr 25Oct 24Mar 27Oct 24
1998Apr 6Nov 4Mar 25Nov 5
1997Apr 18Oct 22Apr 18Oct 22
1996Apr 28Oct 10Apr 17Oct 30
1995Apr 24Sep 23Apr 5Sep 23
1994Apr 30Oct 27Apr 7Nov 19
1993Apr 27Sep 30Apr 4Oct 30
1992Apr 28no dataApr 12no data
1991Apr 12Oct 15Apr 2Oct 19
1990Apr 19Oct 19Apr 18Nov 7
1989Apr 20Nov 2Apr 13Nov 2
1988Apr 28Oct 4Apr 21Oct 11
1987no dataOct 7no dataOct 7
1986no dataOct 18no dataNov 9
1985no dataNov 19no dataNov 20
1984Apr 19no dataMar 31no data
1983May 17Oct 30May 10Nov 11
1982no dataSep 26no dataOct 22
1981May 2Oct 18Mar 27Oct 23
1980May 9Oct 5Apr 17Oct 27
1979May 9Oct 13Apr 10Oct 14
1978Apr 22Oct 17Apr 22Oct 24
1977May 9Oct 16Apr 29Nov 11
1976May 6Sep 22Apr 13Oct 17
1975May 13Oct 29Apr 21Oct 30
1974May 7Sep 22Apr 10Oct 2
1973Apr 14Nov 3Apr 13Nov 3
1972May 7Oct 15May 7Oct 17
1971May 3Nov 4Apr 24Nov 6
1970Apr 13Oct 16Apr 10Nov 15
1969Apr 30Oct 15Apr 30Oct 22
1968Apr 29Oct 5Apr 7Oct 30
1967May 12Oct 9Apr 25Oct 12
1966May 13Oct 20May 10Oct 25
1965Apr 28Oct 25Apr 4Oct 29
1964Apr 9Sep 28Apr 9Oct 10
1963May 1Nov 2May 1Nov 2
1962Apr 21Oct 23Apr 20Oct 24
1961May 27Oct 26Apr 16Oct 27
1960Apr 18Oct 20Apr 18Oct 20

"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.