Historical Climate Data

Precipitation Summary

Station: 115901 MOUNT CARROLL, IL

1971-2000 NCDC Normals

Element Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Ann
Prec. (in) 1.43 1.52 2.63 3.67 4.34 4.77 3.83 4.54 3.48 2.73 2.84 2.02 37.80

Precipitation Extremes

Period of Record: 1895-2006


Month
High (in)
Year
Low (in)
Year 		1-Day
Max (in)
Date
Jan 4.36 1960 0.07 1928 1.80 01-12-1960
Feb 4.09 2001 0.14 1982 2.05 02-09-2001
Mar 5.74 1991 0.38 1958 2.87 03-05-1976
Apr 6.62 1950 0.10 1915 2.47 04-30-1984
May 9.94 1970 0.52 1992 4.00 05-14-1983
Jun 10.47 2000 0.33 1922 6.96 06-04-2002
Jul 9.09 1915 0.43 1991 3.29 07-13-1957
Aug 11.63 1981 0.27 1966 3.95 08-09-1930
Sep 10.57 1970 0.09 1979 5.00 09-14-1961
Oct 7.43 1919 0.00 1952 3.85 10-31-1960
Nov 9.45 1934 0.16 1917 3.92 11-17-1952
Dec 5.43 1982 0.28 1989 2.20 12-15-1971
             
Annual 49.45 1998 18.95 1920 6.96 06-04-2002
Winter 9.27 1960 0.81 1899 2.20 12-15-1971
Spring 16.90 1983 2.55 1934 4.00 05-14-1983
Summer 24.52 1981 3.11 1988 6.96 06-04-2002
Fall 18.88 1927 2.69 1939 5.00 09-14-1961

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 7.6 4.1 0.8 0.1
Feb 6.2 3.9 0.8 0.3
Mar 8.9 5.7 1.6 0.5
Apr 10.4 6.9 2.4 0.8
May 10.9 7.3 3.2 1.0
Jun 10.1 7.2 3.5 1.4
Jul 9.1 6.1 2.7 1.0
Aug 10.1 7.3 3.0 1.4
Sep 8.3 5.8 2.0 0.9
Oct 8.1 5.5 1.9 0.6
Nov 8.8 5.6 1.9 0.7
Dec 8.0 4.9 1.2 0.3
         
Annual 106.3 70.2 25.0 8.9
Winter 21.7 13.0 2.8 0.7
Spring 30.1 19.9 7.2 2.3
Summer 29.3 20.6 9.3 3.8
Fall 25.2 16.8 5.8 2.2

Temperature Summary

Station 115901 MOUNT CARROLL, IL

1971-2000 NCDC Normals

Element Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Ann
High °F 28.9 34.6 46.7 60.2 72.1 81.6 85.1 83.1 75.8 63.8 47.3 33.9 59.4
Low °F 7.5 12.6 24.5 34.6 45.7 54.4 58.8 56.4 47.3 35.8 26.1 13.8 34.8
Mean °F 18.2 23.6 35.6 47.4 58.9 68.0 72.0 69.8 61.6 49.8 36.7 23.9 47.1
HDD 1452 1159 911 530 230 38 9 40 152 479 849 1275 7124
CDD 0 0 0 1 42 128 224 187 48 8 0 0 638

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

Temperature Extremes

Period of Record: 1897-2006


Month 		High
Mean °F
Year 		Low
Mean °F
Year 		1-Day
Max °F
Date 		1-Day
Min °F
Date
Jan 33.1 1933 2.7 1977 61 01-27-1944 -31 01-07-1910
Feb 36.6 1998 8.1 1936 70 02-26-2000 -30 02-20-1929
Mar 48.2 1945 22.4 1960 85 03-30-1986 -16 03-01-1962
Apr 56.6 1915 40.9 1907 92 04-10-1930 -2 04-07-1982
May 66.7 1934 51.9 1907 104 05-31-1934 20 05-03-2005
Jun 76.6 1934 61.8 1903 104 06-01-1934 31 06-12-1903
Jul 80.7 1901 67.7 1996 108 07-12-1936 35 07-02-1904
Aug 79.2 1947 64.0 1986 103 08-18-1936 32 08-28-1986
Sep 69.0 1931 55.9 1993 99 09-06-1922 14 09-30-1899
Oct 62.2 1963 41.2 1925 91 10-04-1997 4 10-30-1925
Nov 47.5 2001 26.9 1976 79 11-01-1933 -15 11-29-1976
Dec 35.7 1923 11.4 1985 69 12-05-1998 -28 12-26-1914
                 
Annual 53.6 1965 42.4 1989 108 07-12-1936 -31 01-07-1910
Winter 30.9 1998 11.1 1979 70 02-26-1900 -31 01-07-1910
Spring 54.0 1921 42.0 1996 104 05-31-1934 -16 03-01-1962
Summer 75.5 1921 65.5 1915 108 07-12-1936 31 06-12-1903
Fall 56.3 1963 42.8 1976 99 09-06-1922 -15 11-29-1976

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 18.6 30.4 10.3
Feb 0.0 12.0 26.6 6.6
Mar 0.0 3.8 24.2 0.7
Apr 0.1 0.2 12.7 0.0
May 0.6 0.0 2.4 0.0
Jun 3.9 0.0 0.0 0.0
Jul 6.5 0.0 0.0 0.0
Aug 4.1 0.0 0.0 0.0
Sep 1.3 0.0 1.9 0.0
Oct 0.0 0.0 13.1 0.0
Nov 0.0 2.3 22.0 0.2
Dec 0.0 12.5 29.6 5.3
         
Annual 16.4 49.9 166.4 24.0
Winter 0.0 43.0 86.6 22.2
Spring 0.7 4.0 39.7 0.8
Summer 14.5 0.0 0.1 0.0
Fall 1.3 2.4 37.4 0.2

Snowfall Summary

Station: 115901 MOUNT CARROLL, IL

1971-2000 Averages

Element Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Ann
Snow (in) 10.7 6.9 4.0 1.5 0.0 0.0 0.0 0.0 0.0 0.1 2.6 7.7 33.5

Snowfall Extremes

Period of Record: 1895-2006

Month High (in) Year 1-Day Max (in) Date
Jan 34.3 1979 11.5 01-06-1918
Feb 29.5 1994 12.5 02-10-1960
Mar 24.8 1923 12.0 03-31-1926
Apr 13.6 1921 12.0 04-16-1921
May 2.0 1935 2.0 05-03-1935
Jun 0.0 - - -
Jul 0.0 - - -
Aug 0.0 - - -
Sep 0.1 1942 0.1 09-26-1942
Oct 5.0 1929 4.5 10-23-1929
Nov 13.1 1947 7.6 11-18-1926
Dec 26.3 2000 10.5 12-24-1918
Season (Jul-Jun) 77.5 1978-1979 12.5 02-10-1960

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 3.6 2.5 1.6 0.3
Feb 3.6 2.5 1.6 0.3
Mar 2.1 1.5 0.8 0.2
Apr 0.6 0.5 0.2 0.1
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 0.0 0.0
Nov 1.2 0.8 0.6 0.2
Dec 4.2 3.0 1.7 0.2
Annual 16.8 11.9 7.2 1.4

Growing Season Summary

Station: 115901 MOUNT CARROLL, 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 75 256 584 837 984 918 643 321 77 8 4547
45 0 2 38 153 434 687 829 763 495 204 36 3 3515
50 0 0 17 81 294 537 674 608 352 116 15 1 2600
55 0 0 7 38 179 389 519 454 228 55 4 0 1805
60 0 0 2 17 95 250 366 304 131 21 0 0 1144
50** 1 7 55 176 371 545 655 605 421 226 51 6 3015

**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 5/10 4/19 4/23 5/28 5/31 9/27 8/28 9/14 10/08 10/15
30 5/03 4/10 4/21 5/16 5/29 10/03 9/06 9/22 10/13 10/16
28 4/28 4/06 4/11 5/10 5/29 10/06 9/07 9/23 10/20 11/01
24 4/12 3/24 3/30 4/29 5/09 10/15 9/23 9/27 11/05 11/16
20 4/06 3/17 3/22 4/21 4/23 11/03 10/02 10/10 11/18 11/21
16 4/04 2/21 3/13 4/17 4/22 11/13 10/11 10/21 11/27 11/30

Length of Growing Season (Days)

Derived from 1971-2000 Averages

Temp °F Median Shortest 10% 90% Longest
32 140 99 119 159 178
30 153 123 135 170 179
28 163 123 137 180 191
24 184 137 161 213 226
20 212 168 187 234 243
16 221 175 202 252 274

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