Historical Climate Data

Precipitation Summary

Station: 114530 JOLIET BRANDON RD DAM, IL

1971-2000 NCDC Normals

Element Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Ann
Prec. (in) 1.58 1.64 2.46 3.75 3.87 4.22 4.34 3.82 3.14 2.70 3.00 2.44 36.96

Precipitation Extremes

Period of Record: 1943-2006


Month
High (in)
Year
Low (in)
Year 		1-Day
Max (in)
Date
Jan 5.90 2005 0.05 1981 1.90 01-14-1995
Feb 5.59 1997 0.00 1987 2.75 02-21-1997
Mar 5.37 1944 0.26 1958 2.32 03-25-1954
Apr 9.26 1947 0.53 1971 4.92 04-05-1947
May 7.62 1975 0.67 1992 3.20 05-12-2002
Jun 11.69 1993 0.38 1988 5.13 06-13-1981
Jul 17.37 1996 0.13 1991 13.60 07-18-1996
Aug 10.05 1972 0.47 1996 4.00 08-15-1958
Sep 13.20 1961 0.04 1979 3.67 09-01-1977
Oct 8.71 1954 0.16 1964 3.75 10-11-1954
Nov 8.18 1985 0.52 1999 2.54 11-28-1990
Dec 7.28 1982 0.27 1995 3.34 12-03-1982
             
Annual 50.15 1972 21.38 1963 13.60 07-18-1996
Winter 13.09 1950 1.41 1961 3.34 12-03-1982
Spring 17.92 1973 3.61 1992 4.92 04-05-1947
Summer 22.87 1993 3.43 1991 13.60 07-18-1996
Fall 18.31 1961 3.40 1963 3.75 10-11-1954

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 10.3 4.2 0.8 0.2
Feb 8.5 4.4 0.8 0.3
Mar 10.7 5.8 1.6 0.3
Apr 11.6 7.1 2.4 0.9
May 11.1 7.5 2.8 0.8
Jun 9.8 7.1 2.8 0.9
Jul 9.1 6.1 2.8 1.1
Aug 9.4 6.0 2.6 1.0
Sep 8.4 5.3 2.0 0.8
Oct 9.0 5.0 2.0 0.6
Nov 10.8 6.1 1.9 0.7
Dec 11.1 5.1 1.5 0.4
         
Annual 119.8 69.5 23.9 8.1
Winter 29.8 13.7 3.1 0.9
Spring 33.4 20.4 6.8 2.0
Summer 28.3 19.1 8.1 3.0
Fall 28.2 16.4 5.9 2.1

Temperature Summary

Station 114530 JOLIET BRANDON RD DAM, IL

1971-2000 NCDC Normals

Element Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Ann
High °F 29.9 35.2 46.8 59.5 71.6 81.3 84.6 82.4 76.0 64.1 48.3 35.2 59.6
Low °F 13.5 18.6 27.6 36.9 47.5 58.2 62.8 60.7 52.9 41.2 31.4 19.5 39.2
Mean °F 21.7 26.9 37.2 48.2 59.6 69.8 73.7 71.6 64.5 52.7 39.9 27.4 49.4
HDD 1343 1067 863 505 230 32 4 20 86 391 755 1168 6464
CDD 0 0 0 2 61 174 272 223 70 7 0 0 809

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

Temperature Extremes

Period of Record: 1975-2006


Month 		High
Mean °F
Year 		Low
Mean °F
Year 		1-Day
Max °F
Date 		1-Day
Min °F
Date
Jan 36.0 2006 8.5 1977 65 01-05-1997 -26 01-20-1985
Feb 38.9 1998 13.5 1979 73 02-26-2000 -20 02-05-1979
Mar 44.8 2000 30.1 1984 86 03-30-1986 -7 03-04-2002
Apr 54.7 1977 44.0 1982 92 04-26-1986 11 04-07-1982
May 68.8 1977 54.7 1997 93 05-29-1991 30 05-01-1978
Jun 74.9 1991 64.7 1982 104 06-26-1988 35 06-13-1985
Jul 78.2 1999 70.3 1992 103 07-14-1995 47 07-06-1983
Aug 78.7 1995 67.7 1992 102 08-02-1988 39 08-29-1986
Sep 70.4 2005 59.8 1993 97 09-09-1978 32 09-23-1983
Oct 57.1 2000 47.1 1987 88 10-05-2005 17 10-29-1976
Nov 50.4 2001 31.8 1976 78 11-07-1975 -2 11-26-1977
Dec 36.3 1982 15.4 1983 70 12-03-1982 -20 12-24-1983
                 
Annual 54.0 1998 46.6 1989 104 06-26-1988 -26 01-20-1985
Winter 32.8 1998 16.1 1979 73 02-26-1900 -26 01-20-1985
Spring 55.6 1977 44.7 1996 93 05-29-1991 -7 03-04-1902
Summer 76.2 1988 68.3 1992 104 06-26-1988 35 06-13-1985
Fall 61.4 2000 47.9 1976 97 09-09-1978 -2 11-26-1977

Temperature Threshold Climatology

Derived from 1975-2000 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 17.6 29.2 6.6
Feb 0.0 11.3 24.5 3.3
Mar 0.0 3.5 21.4 0.0
Apr 0.1 0.1 6.8 0.0
May 1.0 0.0 0.6 0.0
Jun 4.2 0.0 0.0 0.0
Jul 6.8 0.0 0.0 0.0
Aug 3.6 0.0 0.0 0.0
Sep 1.7 0.0 0.1 0.0
Oct 0.0 0.0 4.1 0.0
Nov 0.0 2.1 17.6 0.1
Dec 0.0 10.8 27.3 3.1
         
Annual 17.1 45.8 132.9 13.2
Winter 0.0 39.6 81.0 12.9
Spring 1.1 3.6 29.2 0.0
Summer 14.6 0.0 0.0 0.0
Fall 1.7 2.0 21.4 0.1

Snowfall Summary

Station: 114530 JOLIET BRANDON RD DAM, IL

1971-2000 Averages

Element Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Ann
Snow (in) 5.6 1.3 0.7 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.3 2.4 10.3

Snowfall Extremes

Period of Record: 1943-2006

Month High (in) Year 1-Day Max (in) Date
Jan 18.3 1999 12.0 01-27-1967
Feb 14.5 1963 6.0 02-24-1994
Mar 18.1 1965 8.0 03-03-1954
Apr 2.0 1951 2.0 04-24-1967
May 0.0 - - -
Jun 0.0 - - -
Jul 0.0 - - -
Aug 0.0 - - -
Sep 0.0 - - -
Oct 3.0 1967 3.0 10-27-1967
Nov 9.3 1951 7.0 11-07-1951
Dec 26.0 2000 8.0 12-12-2000
Season (Jul-Jun) 52.1 1951-1952 12.0 01-27-1967

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 1.5 0.8 0.6 0.1
Feb 1.5 0.8 0.6 0.1
Mar 0.4 0.3 0.2 0.0
Apr 0.0 0.0 0.0 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 0.1 0.0 0.0 0.0
Dec 1.5 0.7 0.5 0.3
Annual 3.0 1.9 1.3 0.5

Growing Season Summary

Station: 114530 JOLIET BRANDON RD DAM, 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 20 102 303 635 907 1066 1000 746 398 123 21 5220
45 1 6 56 189 482 757 911 845 597 263 64 9 4097
50 0 1 28 103 338 608 756 690 450 155 30 4 3099
55 0 0 11 51 211 458 601 535 308 79 11 1 2223
60 0 0 4 23 115 316 447 380 186 32 2 0 1479
50** 3 12 64 178 384 596 727 675 468 234 66 11 3350

**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 4/22 3/28 4/05 5/09 5/12 10/18 9/23 10/06 11/03 11/06
30 4/14 3/28 4/05 4/30 5/12 10/23 10/05 10/08 11/04 11/19
28 4/09 3/24 3/28 4/20 4/23 11/03 10/13 10/20 11/19 12/03
24 3/22 3/09 3/14 4/10 4/19 11/08 10/22 10/26 11/30 12/05
20 3/17 2/28 3/02 4/06 4/08 11/22 10/29 11/05 12/11 12/22
16 3/10 2/09 2/15 3/24 4/08 12/04 11/03 11/12 12/21 12/23

Length of Growing Season (Days)

Derived from 1975-2000 Averages

Temp °F Median Shortest 10% 90% Longest
32 177 137 155 210 214
30 187 159 166 213 225
28 209 189 196 225 238
24 225 202 206 256 265
20 251 212 218 281 284
16 266 221 236 303 310

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