Historical Climate Data

Precipitation Summary

Station: 116616 PARK FOREST, IL

1971-2000 NCDC Normals

Element Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Ann
Prec. (in) 1.79 1.64 2.73 3.80 4.14 4.66 4.08 3.82 3.15 2.79 3.38 2.67 38.65

Precipitation Extremes

Period of Record: 1952-2006


Month
High (in)
Year
Low (in)
Year 		1-Day
Max (in)
Date
Jan 5.36 2005 0.08 1981 1.85 01-10-1975
Feb 4.98 1997 0.03 1987 2.27 02-21-1997
Mar 6.30 1976 0.25 1958 1.97 03-16-1984
Apr 7.17 1999 0.47 1971 3.88 04-17-2006
May 8.97 1996 0.93 1964 6.43 05-22-1982
Jun 11.18 1993 0.55 1965 4.25 06-06-1974
Jul 11.67 2003 0.54 1991 6.55 07-18-1996
Aug 9.37 2006 0.41 1996 4.95 08-16-1968
Sep 10.78 1961 0.09 1979 3.19 09-23-1961
Oct 10.13 1954 0.25 1964 5.93 10-10-1954
Nov 8.25 1990 0.36 1976 3.40 11-28-1990
Dec 6.84 1982 0.24 1962 3.90 12-25-1965
             
Annual 54.59 2006 24.56 1962 6.55 07-18-1996
Winter 9.71 1974 0.98 1961 3.90 12-25-1965
Spring 16.89 1991 4.83 1971 6.43 05-22-1982
Summer 23.03 1993 6.28 2002 6.55 07-18-1996
Fall 16.65 1961 2.43 1956 5.93 10-10-1954

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 9.3 4.3 1.0 0.2
Feb 8.2 4.2 0.7 0.2
Mar 10.2 6.5 1.6 0.4
Apr 11.7 7.6 2.7 0.9
May 10.8 7.0 2.7 1.0
Jun 9.8 6.9 3.2 1.3
Jul 9.1 6.1 2.7 1.1
Aug 9.2 6.0 2.5 1.4
Sep 9.0 6.1 2.0 0.6
Oct 9.0 5.6 1.8 0.4
Nov 11.3 6.2 2.2 0.9
Dec 10.1 5.3 1.3 0.5
         
Annual 117.8 71.7 24.4 9.0
Winter 27.7 13.8 3.0 0.9
Spring 32.7 21.1 7.0 2.3
Summer 28.2 19.0 8.4 3.8
Fall 29.3 17.9 6.0 1.9

Temperature Summary

Station 116616 PARK FOREST, IL

1971-2000 NCDC Normals

Element Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Ann
High °F 29.2 34.7 45.7 58.1 70.0 80.0 83.7 81.5 74.7 63.0 47.5 34.8 58.6
Low °F 14.8 19.7 29.7 39.4 50.0 59.5 64.7 63.3 55.2 43.2 32.8 21.1 41.1
Mean °F 22.0 27.2 37.7 48.8 60.0 69.8 74.2 72.4 65.0 53.1 40.2 28.0 49.9
HDD 1333 1059 846 491 222 29 1 15 85 380 745 1149 6355
CDD 0 0 0 3 66 171 286 245 84 11 0 0 866

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

Temperature Extremes

Period of Record: 1952-2006


Month 		High
Mean °F
Year 		Low
Mean °F
Year 		1-Day
Max °F
Date 		1-Day
Min °F
Date
Jan 35.5 2006 8.0 1977 65 01-24-1967 -27 01-20-1985
Feb 37.6 1998 14.7 1979 71 02-26-2000 -18 02-03-1996
Mar 44.7 1973 24.3 1960 83 03-30-1986 -6 03-04-2002
Apr 55.2 1955 43.7 1982 89 04-23-1980 9 04-07-1982
May 67.8 1977 53.9 1966 94 05-29-1991 25 05-10-1966
Jun 75.1 1952 62.8 1958 102 06-26-1988 36 06-11-1972
Jul 78.2 1999 70.3 1992 102 07-16-1988 45 07-05-1972
Aug 78.5 1995 67.0 2004 103 08-02-1988 41 08-28-1986
Sep 69.9 1978 59.6 1975 99 09-01-1953 29 09-23-1995
Oct 63.1 1963 44.8 1988 91 10-06-1963 17 10-29-1952
Nov 48.5 2001 31.8 1976 77 11-06-1978 0 11-28-1955
Dec 36.8 1982 15.5 1989 70 12-03-1982 -21 12-25-1983
                 
Annual 53.6 1998 46.6 1979 103 08-02-1988 -27 01-20-1985
Winter 32.2 1998 16.7 1979 71 02-26-1900 -27 01-20-1985
Spring 55.0 1977 42.1 1960 94 05-29-1991 -6 03-04-1902
Summer 75.4 1995 67.7 1992 103 08-02-1988 36 06-11-1972
Fall 57.6 1963 47.5 1976 99 09-01-1953 0 11-28-1955

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 18.2 29.4 5.9
Feb 0.0 11.9 24.8 3.0
Mar 0.0 4.2 21.0 0.1
Apr 0.0 0.2 7.5 0.0
May 0.7 0.0 0.6 0.0
Jun 3.6 0.0 0.0 0.0
Jul 5.8 0.0 0.0 0.0
Aug 3.3 0.0 0.0 0.0
Sep 1.1 0.0 0.1 0.0
Oct 0.0 0.0 4.6 0.0
Nov 0.0 2.3 16.5 0.0
Dec 0.0 11.0 27.2 2.6
         
Annual 14.7 48.4 132.0 11.6
Winter 0.0 41.2 81.4 11.5
Spring 0.7 4.4 29.2 0.1
Summer 12.8 0.0 0.0 0.0
Fall 1.1 2.3 21.1 0.0

Snowfall Summary

Station: 116616 PARK FOREST, IL

1971-2000 Averages

Element Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Ann
Snow (in) 10.4 7.3 4.3 0.9 0.0 0.0 0.0 0.0 0.0 0.3 1.2 7.0 31.4

Snowfall Extremes

Period of Record: 1952-2006

Month High (in) Year 1-Day Max (in) Date
Jan 30.8 1979 14.0 01-26-1967
Feb 18.9 1994 11.0 02-11-1956
Mar 16.1 1993 10.0 03-02-1954
Apr 9.5 1982 7.0 04-06-1982
May 0.0 - - -
Jun 0.0 - - -
Jul 0.0 - - -
Aug 0.0 - - -
Sep 0.0 - - -
Oct 3.0 1989 3.0 10-20-1989
Nov 6.1 1955 4.0 11-25-2004
Dec 32.7 2000 10.0 12-23-1969
Season (Jul-Jun) 57.6 1978-1979 14.0 01-26-1967

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 4.2 2.9 1.8 0.1
Feb 4.2 2.9 1.8 0.1
Mar 2.3 1.5 0.9 0.1
Apr 0.4 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 0.2 0.1 0.0 0.0
Nov 1.0 0.4 0.3 0.0
Dec 3.7 2.5 1.5 0.3
Annual 17.0 11.1 6.8 1.0

Growing Season Summary

Station: 116616 PARK FOREST, 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 6 16 97 284 613 885 1053 987 736 391 121 19 5174
45 1 5 52 176 462 736 898 833 587 260 63 8 4062
50 0 1 26 98 322 586 743 679 440 156 29 3 3073
55 0 0 11 49 203 439 588 526 301 81 10 1 2205
60 0 0 4 22 114 301 434 373 185 34 2 0 1470
50** 2 9 57 162 365 579 718 667 459 224 61 10 3297

**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 4/28 3/30 4/09 5/11 5/28 10/14 9/23 9/29 11/04 11/06
30 4/19 3/26 4/05 5/04 5/12 10/19 9/22 10/05 11/07 11/17
28 4/11 3/24 4/03 4/28 5/12 11/03 10/02 10/08 11/15 11/20
24 4/07 3/13 3/19 4/16 4/23 11/08 10/07 10/21 11/30 12/05
20 3/20 2/21 3/05 4/08 4/10 11/22 10/24 11/06 12/06 12/22
16 3/14 2/12 2/21 3/30 4/09 12/03 11/02 11/11 12/20 12/24

Length of Growing Season (Days)

Derived from 1971-2000 Averages

Temp °F Median Shortest 10% 90% Longest
32 165 143 151 205 213
30 180 159 161 219 222
28 201 160 174 223 228
24 216 177 197 247 255
20 243 213 219 269 282
16 266 222 236 284 296

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