All-time weather records — Mount Vernon, IA

Record high
109.9°F
July 6, 1911
Record low
-33.0°F
January 16, 2009
Wettest day
7.78 in
September 15, 1914

Climate change signal in Mount Vernon

10.7%

of Mount Vernon's all-time daily heat records were set in the last decade (39 of 366 records since 2015).

3%

of all-time daily cold records were set in the last decade (11 of 366 records since 2015).

If records were spread evenly across the station's history, you'd expect roughly 5% per decade. Decade-by-decade, here's where each record-breaking day was set:

Decade Heat records set # Cold records set #
1890s
33
20
1900s
19
24
1910s
47
34
1920s
48
70
1930s
60
39
1940s
17
31
1950s
13
30
1960s
7
17
1970s
8
33
1980s
20
23
1990s
18
18
2000s
21
8
2010s
30
18
2020s
25
1

Records are the all-time daily extremes that are still standing — each daily record can only be held by one year. The station's earliest hot record was set in 1893, the latest in 2026. Period of observation: 1892-2026.

Records by month

Month Hottest day Coldest day Wettest day
January 68.0°F — Jan 31, 1989 -33.0°F — Jan 16, 2009 2.92 in — Jan 12, 1960
February 75.9°F — Feb 22, 2017 -27.9°F — Feb 2, 1996 2.50 in — Feb 9, 1898
March 89.1°F — Mar 21, 2026 -17.0°F — Mar 1, 1962 2.61 in — Mar 31, 1998
April 93.9°F — Apr 15, 1896 3.0°F — Apr 6, 1982 3.30 in — Apr 8, 1896
May 104.0°F — May 31, 1934 24.1°F — May 7, 1925 3.40 in — May 26, 1986
June 102.9°F — Jun 26, 1931 36.0°F — Jun 4, 1945 4.76 in — Jun 4, 2002
July 109.9°F — Jul 6, 1911 42.1°F — Jul 2, 1924 6.63 in — Jul 5, 1993
August 108.0°F — Aug 3, 1930 37.0°F — Aug 30, 1915 4.71 in — Aug 5, 1968
September 105.1°F — Sep 4, 1925 21.9°F — Sep 30, 1899 7.78 in — Sep 15, 1914
October 93.9°F — Oct 3, 1997 -2.0°F — Oct 30, 1925 2.84 in — Oct 2, 2019
November 80.1°F — Nov 8, 1999 -9.9°F — Nov 26, 1977 2.64 in — Nov 2, 1961
December 69.1°F — Dec 4, 1998 -27.9°F — Dec 28, 1924 1.89 in — Dec 15, 1971

Click a month to see every daily record for that month in Mount Vernon.