Last Frost Day

Frost history / Rockville 5 N, OR

Rockville 5 N, OR: frost dates by year

Last spring and first fall frost at NOAA station USC00357277, 1964 to 2012, measured from daily minimum temperatures.

Elevation 3,670 ft, 43.364, -117.114. Download the data (JSON), NOAA daily records

Summary at 32°F

Last spring frostFirst fall frost
MedianJun 19Sep 6
EarliestMay 23 (1971)Aug 6 (1969)
LatestJul 21 (1987)Oct 4 (1994)
Trend1.1 days earlier per decade1.5 days later per decade
Years with data4847

At 28°F (hard freeze) the median last spring date is May 22 and the median first fall date is Sep 16.

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)

May 15May 30Jun 14Jun 29Jul 14Jul 29197019801990200020101964: May 261965: Jun 271966: Jun 251967: Jun 31968: Jun 301969: Jun 281970: Jun 11971: May 231972: May 271973: Jul 11974: Jun 91975: Jun 271976: Jun 271977: Jul 71978: Jun 161979: Jun 81980: Jun 271981: Jul 81982: Jun 91983: Jun 131984: Jun 91985: Jun 271986: Jul 171987: Jul 211988: Jul 71989: Jun 211990: Jun 131991: Jun 181992: Jun 141993: Jul 121994: Jun 171995: Jun 201996: Jun 191997: Jun 241998: Jun 271999: Jun 102000: Jun 12001: Jun 192002: Jun 192003: Jun 232004: May 242005: Jun 132006: May 302007: May 292008: Jun 122010: Jun 182011: Jun 32012: Jun 20

First fall frost (32°F)

Jul 29Aug 13Aug 28Sep 12Sep 27Oct 12197019801990200020101964: Aug 201965: Aug 291966: Aug 311967: Sep 131968: Sep 31969: Aug 61970: Sep 91972: Sep 71973: Aug 281974: Sep 131975: Sep 21976: Aug 171977: Aug 311978: Sep 121979: Sep 101980: Sep 51981: Sep 41982: Sep 111983: Sep 91984: Sep 121985: Sep 101986: Sep 151987: Aug 171988: Aug 221989: Sep 31990: Sep 171991: Sep 151992: Aug 231993: Aug 251994: Oct 41996: Sep 61997: Sep 191998: Sep 201999: Aug 312000: Sep 32001: Sep 72002: Sep 82003: Sep 132004: Sep 212005: Sep 102006: Aug 312007: Sep 92008: Sep 22009: Sep 82010: Aug 242011: Sep 42012: Aug 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
2012Jun 20Aug 25May 19Sep 11
2011Jun 3Sep 4May 24Oct 9
2010Jun 18Aug 24May 21Oct 12
2009no dataSep 8no dataOct 1
2008Jun 12Sep 2May 13Oct 9
2007May 29Sep 9May 6Oct 6
2006May 30Aug 31May 10Sep 15
2005Jun 13Sep 10May 1Sep 11
2004May 24Sep 21Apr 30Oct 10
2003Jun 23Sep 13May 20Sep 18
2002Jun 19Sep 8May 24Sep 11
2001Jun 19Sep 7May 7Sep 8
2000Jun 1Sep 3Jun 1Sep 23
1999Jun 10Aug 31May 16Sep 13
1998Jun 27Sep 20Apr 27Sep 23
1997Jun 24Sep 19May 8Sep 28
1996Jun 19Sep 6Jun 19Sep 6
1995Jun 20no dataApr 26no data
1994Jun 17Oct 4Jun 8Oct 4
1993Jul 12Aug 25Jul 12Sep 21
1992Jun 14Aug 23May 22Aug 24
1991Jun 18Sep 15May 26Sep 22
1990Jun 13Sep 17May 25Oct 7
1989Jun 21Sep 3May 24Sep 13
1988Jul 7Aug 22May 4Sep 12
1987Jul 21Aug 17May 22Sep 16
1986Jul 17Sep 15Jul 17Sep 21
1985Jun 27Sep 10May 13Sep 16
1984Jun 9Sep 12Jun 9Sep 14
1983Jun 13Sep 9May 14Sep 20
1982Jun 9Sep 11Jun 8Sep 11
1981Jul 8Sep 4May 17Sep 23
1980Jun 27Sep 5Apr 15Sep 23
1979Jun 8Sep 10May 31Sep 11
1978Jun 16Sep 12May 25Sep 16
1977Jul 7Aug 31Jul 7Sep 9
1976Jun 27Aug 17Jun 26Sep 7
1975Jun 27Sep 2May 26Sep 18
1974Jun 9Sep 13May 31Sep 13
1973Jul 1Aug 28Jun 18Sep 16
1972May 27Sep 7May 10Sep 15
1971May 23no dataMay 20no data
1970Jun 1Sep 9May 15Sep 12
1969Jun 28Aug 6May 3Aug 29
1968Jun 30Sep 3Jun 30Sep 22
1967Jun 3Sep 13May 26Sep 13
1966Jun 25Aug 31Jun 25Oct 1
1965Jun 27Aug 29May 18Aug 30
1964May 26Aug 20May 23Aug 29

"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.