Historical Climate Data

Precipitation Summary

Station: 114823 LA HARPE, IL

1971-2000 NCDC Normals

Element Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Ann
Prec. (in) 1.47 1.68 2.86 3.82 4.58 4.38 4.54 3.54 3.99 2.85 3.15 2.28 39.14

Precipitation Extremes

Period of Record: 1895-2006


Month
High (in)
Year
Low (in)
Year 		1-Day
Max (in)
Date
Jan 10.38 1897 0.08 1986 4.00 01-19-1907
Feb 4.99 1997 0.02 2006 3.41 02-21-1997
Mar 7.66 1985 0.28 1956 5.08 03-04-1985
Apr 8.28 1964 0.76 1971 4.52 04-24-1976
May 12.57 1899 0.50 1964 4.40 05-21-1899
Jun 12.60 1905 0.49 1963 10.25 06-10-1905
Jul 14.54 1948 0.10 1916 5.02 07-25-1948
Aug 12.36 1970 0.38 1910 5.45 08-14-1898
Sep 13.21 1970 0.12 1940 4.50 09-12-1928
Oct 13.61 1941 0.00 1964 4.74 10-03-1986
Nov 8.45 1985 0.08 1917 3.20 11-30-2006
Dec 6.00 1982 0.23 1976 3.37 12-10-2003
             
Annual 51.20 1973 20.80 1988 10.25 06-10-1905
Winter 13.20 1897 1.42 1920 4.00 01-19-1907
Spring 18.88 1899 3.05 1956 5.08 03-04-1985
Summer 25.50 1902 3.38 1936 10.25 06-10-1905
Fall 22.79 1941 1.95 1956 4.74 10-03-1986

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 6.0 3.9 0.7 0.3
Feb 5.1 3.9 0.9 0.3
Mar 7.9 6.2 1.7 0.5
Apr 9.2 7.1 2.7 0.9
May 10.8 8.2 3.0 1.3
Jun 8.7 6.7 3.0 1.2
Jul 8.3 6.4 2.8 1.5
Aug 8.4 6.4 2.5 1.1
Sep 7.5 5.9 2.8 1.0
Oct 7.7 5.4 1.6 0.7
Nov 8.1 6.3 2.4 0.5
Dec 6.7 5.1 1.2 0.5
         
Annual 94.6 71.7 25.4 9.8
Winter 17.9 12.9 2.8 1.0
Spring 28.0 21.6 7.4 2.7
Summer 25.4 19.5 8.3 3.8
Fall 23.3 17.7 6.9 2.3

Temperature Summary

Station 114823 LA HARPE, IL

1971-2000 NCDC Normals

Element Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Ann
High °F 31.7 37.6 50.0 62.4 73.3 82.7 87.0 84.7 77.3 65.9 49.6 36.5 61.6
Low °F 13.3 18.2 28.7 39.4 50.5 60.0 64.3 62.3 53.6 42.3 30.5 19.2 40.2
Mean °F 22.5 27.9 39.4 50.9 61.9 71.4 75.7 73.5 65.5 54.1 40.1 27.9 50.9
HDD 1318 1039 796 429 173 17 1 14 86 350 749 1152 6124
CDD 0 0 0 6 77 207 331 277 100 11 0 0 1009

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 38.5 1933 10.3 1940 70 01-07-1907 -23 01-18-1930
Feb 39.2 1930 13.8 1936 76 02-24-1930 -30 02-13-1905
Mar 52.4 1946 23.9 1960 88 03-23-1910 -13 03-05-1960
Apr 59.6 1896 44.9 1907 94 04-10-1930 9 04-05-1920
May 70.3 1962 55.1 1990 105 05-31-1934 26 05-07-1906
Jun 80.5 1934 65.2 1916 108 06-29-1934 37 06-12-1903
Jul 84.1 1936 69.1 1924 110 07-15-1936 42 07-14-1975
Aug 82.0 1947 66.4 1915 113 08-09-1934 36 08-31-1915
Sep 74.2 1897 59.5 1993 103 09-01-1913 23 09-30-1899
Oct 66.0 1963 43.7 1925 96 10-04-2006 1 10-30-1925
Nov 50.4 1931 32.8 1996 83 11-01-1950 -3 11-30-1929
Dec 39.6 1965 13.9 2000 72 12-05-1998 -26 12-28-1924
                 
Annual 56.1 1918 48.3 1996 113 08-09-1934 -30 02-13-1905
Winter 36.2 1932 17.6 1936 76 02-24-1930 -30 02-13-1905
Spring 57.6 1977 45.7 1960 105 05-31-1934 -13 03-05-1960
Summer 80.4 1934 68.2 1915 113 08-09-1934 36 08-31-1915
Fall 61.2 1931 47.9 1976 103 09-01-1913 -3 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 14.9 29.7 6.6
Feb 0.0 9.1 24.8 3.4
Mar 0.0 2.4 20.3 0.2
Apr 0.1 0.0 6.9 0.0
May 0.8 0.0 0.5 0.0
Jun 5.5 0.0 0.0 0.0
Jul 11.3 0.0 0.0 0.0
Aug 7.4 0.0 0.0 0.0
Sep 2.6 0.0 0.4 0.0
Oct 0.1 0.0 6.7 0.0
Nov 0.0 1.9 19.2 0.2
Dec 0.0 9.9 28.0 3.3
         
Annual 27.8 38.1 136.1 13.7
Winter 0.0 33.9 82.6 13.4
Spring 0.9 2.5 27.7 0.2
Summer 24.2 0.0 0.0 0.0
Fall 2.7 1.9 26.3 0.2

Snowfall Summary

Station: 114823 LA HARPE, IL

1971-2000 Averages

Element Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Ann
Snow (in) 7.6 4.7 3.4 0.9 0.0 0.0 0.0 0.0 0.0 0.0 1.9 6.1 24.6

Snowfall Extremes

Period of Record: 1895-2006

Month High (in) Year 1-Day Max (in) Date
Jan 27.0 1930 10.0 01-13-1927
Feb 13.5 1905 10.0 02-18-1908
Mar 20.0 1960 8.0 03-09-1998
Apr 12.0 1920 12.0 04-04-1920
May 1.5 1917 1.5 05-04-1917
Jun 0.0 - - -
Jul 0.0 - - -
Aug 0.0 - - -
Sep 3.1 1942 3.1 09-25-1942
Oct 9.0 1916 9.0 10-20-1916
Nov 12.0 1974 8.0 11-30-1974
Dec 19.0 2000 13.0 12-24-1918
Season (Jul-Jun) 51.5 1978-1979 13.0 12-24-1918

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 2.4 2.1 1.2 0.1
Feb 2.4 2.1 1.2 0.1
Mar 1.7 1.6 0.7 0.1
Apr 0.3 0.3 0.2 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 0.0 0.0 0.0 0.0
Nov 1.0 0.9 0.3 0.1
Dec 2.9 2.7 1.5 0.2
Annual 12.0 11.0 5.7 0.9

Growing Season Summary

Station: 114823 LA HARPE, 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 7 29 130 352 687 942 1099 1026 754 430 125 20 5606
45 1 11 70 231 533 792 944 871 605 293 66 8 4432
50 0 2 35 135 384 642 789 716 458 180 30 3 3380
55 0 0 15 67 248 493 634 561 318 96 11 0 2450
60 0 0 4 29 139 347 480 407 199 42 2 0 1652
50** 6 22 90 221 427 625 739 685 484 273 79 14 3670

**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 4/23 4/02 4/08 5/03 5/11 10/11 9/21 9/24 10/24 11/03
30 4/13 3/25 4/03 4/28 5/10 10/18 9/23 10/02 11/04 11/09
28 4/09 3/24 3/27 4/22 5/06 10/21 10/01 10/05 11/06 11/12
24 4/05 3/15 3/17 4/14 4/18 11/02 10/08 10/20 11/19 11/22
20 3/24 3/03 3/12 4/10 4/13 11/12 10/20 10/28 11/27 11/30
16 3/12 2/07 2/11 3/31 4/07 11/21 11/02 11/07 12/08 12/21

Length of Growing Season (Days)

Derived from 1971-2000 Averages

Temp °F Median Shortest 10% 90% Longest
32 173 137 154 186 207
30 188 147 164 205 211
28 196 164 175 214 227
24 212 189 195 234 239
20 228 194 213 254 264
16 260 215 230 286 300

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