Historical Climate Data

Precipitation Summary

Station: 115943 MT VERNON 3 NE, IL

1971-2000 NCDC Normals

Element Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Ann
Prec. (in) 2.45 2.69 3.98 4.44 4.58 3.61 3.57 3.27 3.11 2.92 4.37 3.20 42.19

Precipitation Extremes

Period of Record: 1895-2006


Month
High (in)
Year
Low (in)
Year 		1-Day
Max (in)
Date
Jan 11.48 1937 0.04 1986 3.65 01-14-1937
Feb 6.63 1908 0.21 1947 4.31 02-02-1986
Mar 12.04 1945 0.02 1910 3.90 03-25-1913
Apr 9.91 1957 0.92 1915 4.79 04-29-1996
May 12.89 1995 0.35 1914 5.03 05-17-1990
Jun 10.85 1928 0.14 1933 4.10 06-22-1897
Jul 10.83 1948 0.12 1921 4.40 07-16-1956
Aug 14.37 1946 0.30 1909 6.17 08-16-1946
Sep 10.18 1945 0.23 1940 4.25 09-02-1931
Oct 13.91 1919 0.00 1908 4.36 10-26-1919
Nov 13.11 1985 0.20 1914 4.41 11-14-1993
Dec 10.16 1982 0.29 1896 3.00 12-20-1957
             
Annual 63.07 1945 23.39 1980 6.17 08-16-1946
Winter 21.05 1950 2.51 2004 4.31 02-02-1986
Spring 23.37 1945 4.86 1930 5.03 05-17-1990
Summer 18.27 1993 3.00 1991 6.17 08-16-1946
Fall 19.97 1984 3.25 1908 4.41 11-14-1993

Precipitation Threshold Climatology

Derived from 1971-2000 Averages:

*Annual/seasonal totals may differ from the sum of the monthly totals due to rounding.


Month 		# Days
Total ≥ 0.01" 		# Days
Total ≥ 0.10" 		# Days
Total ≥ 0.50" 		# Days
Total ≥ 1.00"
Jan 8.9 5.1 1.6 0.5
Feb 8.1 5.1 1.7 0.6
Mar 10.7 7.1 2.7 0.9
Apr 11.7 8.0 2.8 1.1
May 11.4 7.4 3.0 1.2
Jun 9.9 6.7 2.6 0.9
Jul 8.3 5.6 2.4 1.2
Aug 7.6 5.0 2.3 1.0
Sep 7.7 4.8 2.2 0.8
Oct 8.0 5.2 2.1 0.6
Nov 10.0 6.8 3.0 1.5
Dec 9.6 6.0 2.2 0.7
         
Annual 111.8 72.8 28.9 11.1
Winter 26.5 16.2 5.6 1.9
Spring 33.8 22.6 8.6 3.2
Summer 25.9 17.3 7.3 3.1
Fall 25.7 16.7 7.4 2.9

Temperature Summary

Station 115943 MT VERNON 3 NE, IL

1971-2000 NCDC Normals

Element Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Ann
High °F 37.0 42.8 53.7 64.8 74.5 83.7 87.8 86.3 79.2 68.2 53.9 41.8 64.5
Low °F 18.8 22.9 32.9 43.2 52.6 62.0 66.4 63.9 55.5 43.2 34.1 23.8 43.3
Mean °F 27.9 32.9 43.3 54.0 63.6 72.9 77.1 75.1 67.4 55.7 44.0 32.8 53.9
HDD 1149 899 673 344 137 9 0 5 57 310 630 998 5211
CDD 0 0 0 12 92 245 376 317 127 22 0 0 1191

HDD - heating degree days (base 65F); CDD - cooling degree days (base 65F)

Temperature Extremes

Period of Record: 1895-2006


Month 		High
Mean °F
Year 		Low
Mean °F
Year 		1-Day
Max °F
Date 		1-Day
Min °F
Date
Jan 42.4 1933 12.7 1977 75 01-24-1943 -21 01-19-1994
Feb 44.4 1938 21.9 1899 79 02-29-1972 -22 02-10-1899
Mar 57.0 1946 30.5 1960 92 03-21-1907 -10 03-04-1978
Apr 62.1 1954 47.6 1907 91 04-30-1901 17 04-01-1923
May 73.1 1962 58.5 1924 99 05-28-1911 29 05-01-1903
Jun 80.5 1934 67.9 2003 105 06-25-1914 36 06-01-1924
Jul 86.5 1936 72.0 1924 114 07-14-1936 46 07-23-1947
Aug 85.3 1936 70.2 2004 111 08-17-1936 42 08-29-1986
Sep 76.9 1933 61.4 1918 105 09-15-1939 23 09-30-1899
Oct 66.3 1963 49.6 1987 96 10-05-1938 18 10-24-1981
Nov 55.0 1909 36.4 1976 86 11-01-1938 -5 11-30-1929
Dec 45.3 1923 19.2 1989 78 12-02-1970 -19 12-22-1989
                 
Annual 59.8 1921 51.9 1979 114 07-14-1936 -22 02-10-1999
Winter 42.6 1932 23.8 1977 79 02-29-1972 -22 02-10-1999
Spring 59.9 1921 49.8 1984 99 05-28-1911 -10 03-04-1978
Summer 82.7 1936 71.8 2004 114 07-14-1936 36 06-01-1924
Fall 63.5 1931 51.3 1976 105 09-15-1939 -5 11-30-1929

Temperature Threshold Climatology

Derived from 1971-2000 Averages:

*Annual/seasonal values may differ from the sum of the monthly values due to rounding.


Month 		# Days
High ≥ 90°F 		# Days
High ≤ 32°F 		# Days
Low ≤ 32°F 		# Days
Low ≤ 0°F
Jan 0.0 11.0 26.4 2.6
Feb 0.0 5.8 21.3 1.3
Mar 0.0 1.3 15.4 0.0
Apr 0.0 0.0 4.5 0.0
May 0.8 0.0 0.1 0.0
Jun 6.7 0.0 0.0 0.0
Jul 12.9 0.0 0.0 0.0
Aug 10.3 0.0 0.0 0.0
Sep 3.3 0.0 0.1 0.0
Oct 0.1 0.0 4.9 0.0
Nov 0.0 0.8 13.5 0.0
Dec 0.0 6.0 23.9 1.3
         
Annual 34.2 24.7 110.6 5.3
Winter 0.0 22.6 71.5 5.2
Spring 0.9 1.3 20.0 0.0
Summer 29.8 0.0 0.0 0.0
Fall 3.4 0.8 18.7 0.0

Snowfall Summary

Station: 115943 MT VERNON 3 NE, IL

1971-2000 Averages

Element Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Ann
Snow (in) 6.4 4.5 1.9 0.4 0.0 0.0 0.0 0.0 0.0 0.2 0.7 3.6 17.7

Snowfall Extremes

Period of Record: 1895-2006

Month High (in) Year 1-Day Max (in) Date
Jan 26.0 1979 8.0 01-12-1912
Feb 21.5 1993 14.0 02-21-1912
Mar 17.7 1960 8.0 03-03-1912
Apr 6.0 1904 6.0 04-06-1971
May 0.0 - - -
Jun 0.0 - - -
Jul 0.0 - - -
Aug 0.0 - - -
Sep 0.0 - - -
Oct 5.0 1993 3.0 10-31-1993
Nov 6.6 1958 6.6 11-29-1958
Dec 14.1 2002 10.0 12-05-2002
Season (Jul-Jun) 46.0 1911-1912 14.0 02-21-1912

Snowfall Threshold Climatology

Derived from 1971-2000 Averages

*Annual values may differ from the sum of the monthly values due to rounding.


Month 		# Days
Total ≥ 0.1" 		# Days
Total ≥ 1.0" 		# Days
Total ≥ 2.0" 		# Days
Total ≥ 5.0"
Jan 2.1 1.5 0.9 0.2
Feb 2.1 1.5 0.9 0.2
Mar 0.9 0.6 0.4 0.1
Apr 0.1 0.1 0.1 0.0
May 0.0 0.0 0.0 0.0
Jun 0.0 0.0 0.0 0.0
Jul 0.0 0.0 0.0 0.0
Aug 0.0 0.0 0.0 0.0
Sep 0.0 0.0 0.0 0.0
Oct 0.1 0.1 0.1 0.0
Nov 0.4 0.2 0.1 0.0
Dec 1.6 1.2 0.8 0.2
Annual 8.2 5.9 3.5 0.9

Growing Season Summary

Station: 115943 MT VERNON 3 NE, IL

Growing Degree Day Averages

Derived from 1971-2000 Data

Base Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Ann
40 30 63 199 436 733 998 1152 1081 829 503 210 55 6186
45 12 29 117 305 582 849 998 929 681 360 127 26 4930
50 4 10 62 192 432 699 844 776 534 236 68 10 3804
55 1 3 29 107 290 550 690 624 391 137 31 3 2810
60 0 0 11 51 171 402 536 471 260 65 10 0 1948
50** 18 40 122 260 462 675 792 736 542 317 120 31 4048

**Modified Growing Degree Days: Base 50, Ceiling 86.

Growing Season Summary

Derived from 1971-2000 Averages

Date of Last Spring Occurrence Date of First Fall Occurrence
Temp °F Median Early 90% 10% Late Median Early 90% 10% Late
32 4/12 3/24 4/01 4/30 5/05 10/15 9/22 10/03 10/26 11/06
30 4/10 3/08 3/26 4/23 4/28 10/22 9/23 10/03 11/09 11/14
28 4/06 3/08 3/21 4/18 4/21 10/27 10/08 10/11 11/14 11/25
24 3/25 2/22 3/13 4/10 4/19 11/12 10/13 10/23 11/26 12/05
20 3/12 2/08 2/24 3/31 4/09 11/20 10/24 11/04 12/10 12/17
16 2/27 1/15 2/09 3/19 3/25 12/07 11/04 11/13 12/22 12/25

Length of Growing Season (Days)

Derived from 1971-2000 Averages

Temp °F Median Shortest 10% 90% Longest
32 183 150 164 202 210
30 192 151 175 215 249
28 206 176 187 233 250
24 230 199 206 250 264
20 252 222 229 277 298
16 283 237 251 308 340

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Copyright 2007 Illinois State Water Survey
Jim Angel, State Climatologist, jimangel@illinois.edu
Last Modified: September 11, 2007