Historical Climate Data

Precipitation Summary

Station: 115326 MARENGO, IL

1971-2000 NCDC Normals

Element Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Ann
Prec. (in) 1.48 1.29 2.42 3.71 4.10 4.56 3.86 4.47 3.32 2.61 2.69 1.97 36.48

Precipitation Extremes

Period of Record: 1893-2006


Month
High (in)
Year
Low (in)
Year 		1-Day
Max (in)
Date
Jan 4.51 1965 0.00 2001 2.96 01-24-1938
Feb 3.12 1900 0.00 1969 1.30 02-21-1997
Mar 6.36 1976 0.00 2001 2.10 03-19-1948
Apr 7.88 1993 0.26 1901 2.97 04-29-1909
May 9.89 1996 0.42 1934 3.33 05-11-1905
Jun 10.40 1993 0.19 1922 5.15 06-13-1999
Jul 8.34 1978 0.31 1894 4.07 07-02-1978
Aug 12.24 2002 0.45 1893 8.20 08-22-2002
Sep 10.92 1972 0.00 1979 9.02 09-07-1894
Oct 7.63 1941 0.00 1952 3.20 10-10-1954
Nov 6.25 1985 0.00 2000 2.87 11-03-1935
Dec 5.17 1971 0.00 2000 2.32 12-05-1909
             
Annual 50.79 1972 18.29 2001 9.02 09-07-1894
Winter 9.66 1950 0.00 2001 2.96 01-24-1938
Spring 15.58 1908 2.20 1934 3.33 05-11-1905
Summer 20.69 1987 2.86 1894 8.20 08-22-2002
Fall 19.30 1894 2.19 1999 9.02 09-07-1894

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 8.0 3.8 0.7 0.3
Feb 6.5 3.9 0.6 0.1
Mar 9.5 5.8 1.4 0.4
Apr 10.9 7.2 2.6 0.7
May 9.8 7.1 2.9 1.0
Jun 9.3 6.7 3.0 1.4
Jul 9.1 6.4 2.7 1.2
Aug 9.2 7.2 2.9 1.2
Sep 8.5 5.9 2.2 0.9
Oct 8.1 5.4 1.7 0.5
Nov 8.7 5.8 1.6 0.5
Dec 8.9 5.0 1.1 0.3
         
Annual 106.3 70.0 23.2 8.5
Winter 23.4 12.6 2.4 0.7
Spring 30.2 20.1 6.8 2.1
Summer 27.6 20.3 8.6 3.8
Fall 25.3 17.1 5.5 1.9

Temperature Summary

Station 115326 MARENGO, IL

1971-2000 NCDC Normals

Element Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Ann
High °F 27.9 33.3 44.9 58.6 71.2 81.2 84.5 82.1 75.0 62.9 46.6 33.0 58.4
Low °F 10.6 15.5 26.4 36.7 47.2 57.1 62.0 59.9 50.7 39.1 28.6 16.9 37.6
Mean °F 19.3 24.4 35.7 47.7 59.2 69.2 73.3 71.0 62.9 51.0 37.6 25.0 48.0
HDD 1419 1137 909 521 231 31 4 25 125 439 823 1242 6906
CDD 0 0 0 2 51 156 260 211 60 5 0 0 745

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

Temperature Extremes

Period of Record: 1893-2006


Month 		High
Mean °F
Year 		Low
Mean °F
Year 		1-Day
Max °F
Date 		1-Day
Min °F
Date
Jan 33.3 1933 5.8 1912 62 01-25-1950 -29 01-11-1979
Feb 34.6 1954 9.5 1936 73 02-25-1932 -27 02-13-1905
Mar 47.3 1945 21.7 1960 84 03-30-1986 -16 03-08-1943
Apr 55.1 1915 39.4 1907 94 04-30-1926 6 04-07-1982
May 67.0 1977 51.0 1907 107 05-31-1934 22 05-10-1966
Jun 75.8 1933 61.9 1916 107 06-01-1934 29 06-11-1972
Jul 79.6 1901 67.9 1915 109 07-14-1936 39 07-05-1972
Aug 79.5 1947 64.3 1915 107 08-05-1918 37 08-30-1915
Sep 70.4 1998 57.6 1918 103 09-08-1922 24 09-30-1899
Oct 61.2 1947 40.8 1925 90 10-06-1963 8 10-28-1925
Nov 45.4 1931 28.9 1951 80 11-01-1933 -17 11-30-1947
Dec 34.6 1923 12.2 1983 65 12-08-1946 -26 12-27-1950
                 
Annual 51.7 1921 44.6 1893 109 07-14-1936 -29 01-11-1979
Winter 31.1 1932 14.6 1904 73 02-25-1932 -29 01-11-1979
Spring 54.8 1977 42.9 1926 107 05-31-1934 -16 03-08-1943
Summer 75.0 1995 65.2 1915 109 07-14-1936 29 06-11-1972
Fall 56.4 1931 45.9 1976 103 09-08-1922 -17 11-30-1947

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 18.9 30.1 8.4
Feb 0.0 13.1 26.8 5.4
Mar 0.0 4.1 24.1 0.6
Apr 0.0 0.2 11.7 0.0
May 1.2 0.0 1.6 0.0
Jun 5.0 0.0 0.0 0.0
Jul 7.8 0.0 0.0 0.0
Aug 4.2 0.0 0.0 0.0
Sep 1.4 0.0 0.8 0.0
Oct 0.1 0.0 8.7 0.0
Nov 0.0 2.5 20.6 0.2
Dec 0.0 13.2 29.4 4.2
         
Annual 19.8 52.3 154.4 19.1
Winter 0.0 45.4 86.4 18.2
Spring 1.2 4.4 38.2 0.6
Summer 17.0 0.0 0.0 0.0
Fall 1.5 2.5 30.1 0.2

Snowfall Summary

Station: 115326 MARENGO, IL

1971-2000 Averages

Element Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Ann
Snow (in) 11.4 7.6 4.7 1.2 0.1 0.0 0.0 0.0 0.0 0.1 2.5 8.3 35.9

Snowfall Extremes

Period of Record: 1893-2006

Month High (in) Year 1-Day Max (in) Date
Jan 43.0 1979 15.0 01-15-1979
Feb 24.5 1994 9.0 02-06-1967
Mar 24.5 1965 12.0 03-26-1930
Apr 13.5 1970 9.0 04-02-1970
May 4.8 1940 3.5 05-01-1940
Jun 0.0 - - -
Jul 0.0 - - -
Aug 0.0 - - -
Sep 0.0 - - -
Oct 4.0 1929 4.0 10-27-1967
Nov 16.4 1947 6.0 11-24-1981
Dec 21.8 1909 11.0 12-15-1987
Season (Jul-Jun) 58.0 1966-1967 15.0 01-15-1979

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 3.7 3.1 1.7 0.3
Feb 3.7 3.1 1.7 0.3
Mar 2.3 1.7 1.0 0.3
Apr 0.6 0.5 0.2 0.0
May 0.1 0.1 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 0.0 0.0 0.0
Nov 1.4 1.1 0.5 0.1
Dec 4.1 3.2 1.9 0.4
Annual 17.7 13.7 7.5 1.7

Growing Season Summary

Station: 115326 MARENGO, 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 2 8 67 259 587 875 1023 956 680 349 87 8 4836
45 0 2 32 158 437 725 869 801 532 223 43 3 3773
50 0 0 14 86 296 576 715 646 388 127 19 1 2828
55 0 0 5 43 181 428 561 491 255 63 6 0 2001
60 0 0 1 19 100 288 407 339 149 25 0 0 1305
50** 1 6 46 170 371 570 684 632 432 224 51 5 3146

**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 5/07 4/08 4/23 5/17 6/12 10/03 9/20 9/23 10/15 10/16
30 4/28 4/08 4/10 5/10 6/12 10/07 9/22 9/23 10/26 11/08
28 4/22 4/08 4/10 5/08 5/12 10/12 9/22 9/26 11/05 11/11
24 4/11 3/16 4/02 4/22 4/23 11/01 10/02 10/13 11/15 11/22
20 4/04 2/28 3/16 4/11 4/18 11/07 10/14 10/23 11/24 12/08
16 3/22 2/18 3/02 4/06 4/09 11/21 10/31 11/04 12/04 12/08

Length of Growing Season (Days)

Derived from 1971-2000 Averages

Temp °F Median Shortest 10% 90% Longest
32 152 111 135 170 186
30 164 111 138 185 212
28 176 138 145 202 217
24 200 175 185 219 251
20 217 202 204 244 283
16 244 217 222 266 283

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