Historical Climate Data

Precipitation Summary

Station: 114805 LACON 1 N, IL

1971-2000 NCDC Normals

Element Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Ann
Prec. (in) 1.55 1.61 3.08 3.84 4.20 4.14 4.12 3.53 3.49 2.99 3.03 2.32 37.90

Precipitation Extremes

Period of Record: 1950-2006


Month
High (in)
Year
Low (in)
Year 		1-Day
Max (in)
Date
Jan 5.92 1965 0.20 1981 2.50 01-29-2001
Feb 6.25 1997 0.08 1969 3.52 02-21-1997
Mar 6.68 1985 0.91 1966 3.12 03-04-1985
Apr 7.58 1965 0.99 1985 2.65 04-02-1983
May 10.14 1995 0.39 1992 2.35 05-27-1996
Jun 10.10 1990 0.78 1988 4.18 06-20-1964
Jul 12.47 1992 0.32 1988 5.47 07-16-1977
Aug 8.82 1981 0.79 1974 3.25 08-31-1980
Sep 10.87 1961 0.00 1979 4.88 09-06-1989
Oct 8.81 1991 0.03 1964 4.65 10-03-1986
Nov 9.96 1985 0.21 1999 2.77 11-18-1985
Dec 6.12 1971 0.27 1962 2.13 12-05-1999
             
Annual 56.99 1970 22.91 2005 5.47 07-16-1977
Winter 9.33 2001 1.68 1977 3.52 02-21-1997
Spring 18.55 1970 4.30 1971 3.12 03-04-1985
Summer 19.87 1981 4.07 1991 5.47 07-16-1977
Fall 16.65 1970 2.39 2002 4.88 09-06-1989

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 9.2 4.4 0.8 0.3
Feb 7.5 3.7 0.9 0.3
Mar 10.9 6.7 1.9 0.6
Apr 11.2 7.3 2.5 0.9
May 12.0 7.5 2.9 1.3
Jun 9.8 6.8 2.8 1.1
Jul 9.4 6.5 2.5 1.1
Aug 8.9 6.1 2.5 0.9
Sep 8.5 5.2 2.4 0.9
Oct 8.9 5.7 2.1 0.6
Nov 10.1 6.2 2.1 0.7
Dec 9.7 5.1 1.3 0.5
         
Annual 116.2 71.2 24.8 9.3
Winter 26.4 13.2 3.0 1.1
Spring 34.1 21.5 7.3 2.8
Summer 28.2 19.3 7.7 3.1
Fall 27.6 17.1 6.6 2.2

Temperature Summary

Station 114805 LACON 1 N, IL

1971-2000 NCDC Normals

Element Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Ann
High °F 32.0 38.0 50.6 64.1 75.2 83.9 87.2 85.4 78.6 66.5 50.3 36.8 62.4
Low °F 15.2 20.5 30.5 40.6 50.9 60.1 64.3 62.4 54.3 43.1 32.3 20.9 41.3
Mean °F 23.6 29.3 40.6 52.4 63.1 72.0 75.8 73.9 66.5 54.8 41.3 28.9 51.9
HDD 1284 1000 758 388 152 11 2 12 65 328 711 1120 5831
CDD 0 0 0 9 90 221 334 287 107 12 0 0 1060

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

Temperature Extremes

Period of Record: 1950-2006


Month 		High
Mean °F
Year 		Low
Mean °F
Year 		1-Day
Max °F
Date 		1-Day
Min °F
Date
Jan 38.2 2006 9.8 1977 70 01-31-1989 -27 01-05-1999
Feb 39.7 1998 16.7 1979 73 02-27-1976 -21 02-05-1979
Mar 47.4 2000 25.2 1960 81 03-31-1978 -8 03-01-1962
Apr 59.1 1985 47.0 1982 93 04-29-1952 11 04-07-1982
May 70.3 1962 57.7 1966 95 05-01-1952 22 05-10-1966
Jun 76.4 1952 67.1 1982 102 06-25-1988 36 06-11-1972
Jul 80.6 1983 70.4 1971 103 07-14-1977 44 07-30-1971
Aug 80.2 1995 68.0 1967 102 08-01-1988 38 08-28-1986
Sep 72.3 1978 62.0 1993 99 09-08-1978 28 09-23-1974
Oct 61.2 1971 47.5 1952 90 10-04-1969 16 10-29-1952
Nov 49.7 2001 33.4 1976 82 11-01-1950 -3 11-26-1977
Dec 37.8 1982 16.6 1983 71 12-03-1970 -24 12-23-1989
                 
Annual 61.1 1959 49.6 1979 103 07-14-1977 -27 01-05-1999
Winter 34.1 1992 18.3 1979 73 02-27-1976 -27 01-05-1999
Spring 58.0 1977 46.7 1965 95 05-01-1952 -8 03-01-1962
Summer 78.2 1983 70.4 1992 103 07-14-1977 36 06-11-1972
Fall 57.4 1998 49.0 1976 99 09-08-1978 -3 11-26-1977

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 15.2 28.4 5.9
Feb 0.0 9.5 23.3 2.9
Mar 0.0 2.4 18.9 0.1
Apr 0.0 0.0 6.5 0.0
May 1.0 0.0 0.4 0.0
Jun 6.0 0.0 0.0 0.0
Jul 10.5 0.0 0.0 0.0
Aug 7.5 0.0 0.0 0.0
Sep 2.6 0.0 0.2 0.0
Oct 0.0 0.0 4.4 0.0
Nov 0.0 1.4 16.2 0.1
Dec 0.0 9.0 26.7 2.6
         
Annual 28.1 36.5 122.8 11.3
Winter 0.0 33.7 78.3 11.4
Spring 1.1 2.4 25.6 0.1
Summer 24.0 0.0 0.0 0.0
Fall 2.7 1.4 20.5 0.1

Snowfall Summary

Station: 114805 LACON 1 N, IL

1971-2000 Averages

Element Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Ann
Snow (in) 7.5 4.9 2.6 0.7 0.0 0.0 0.0 0.0 0.0 0.1 1.7 6.2 23.7

Snowfall Extremes

Period of Record: 1950-2006

Month High (in) Year 1-Day Max (in) Date
Jan 21.3 1979 12.0 01-02-1999
Feb 13.3 1989 6.0 02-23-1990
Mar 19.0 1960 11.0 03-13-1991
Apr 9.2 1997 8.0 04-11-1997
May 0.0 - - -
Jun 0.0 - - -
Jul 0.0 - - -
Aug 0.0 - - -
Sep 0.0 - - -
Oct 2.0 1967 2.0 10-27-1967
Nov 12.0 1974 6.0 11-27-1975
Dec 23.9 2000 13.0 12-01-2006
Season (Jul-Jun) 44.2 1959-1960 13.0 12-01-2006

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 3.5 1.8 1.1 0.1
Feb 3.5 1.8 1.1 0.1
Mar 1.7 0.9 0.4 0.1
Apr 0.3 0.2 0.1 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 0.0 0.0 0.0
Nov 1.2 0.6 0.3 0.1
Dec 4.3 2.0 1.3 0.2
Annual 15.8 7.9 4.5 0.7

Growing Season Summary

Station: 114805 LACON 1 N, 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 9 33 142 384 708 957 1107 1049 798 475 150 27 5804
45 2 12 80 258 554 807 952 895 648 333 82 12 4609
50 0 3 41 155 404 657 798 742 500 211 39 5 3535
55 0 0 18 82 266 508 643 588 356 118 15 1 2582
60 0 0 6 36 153 360 489 434 228 53 4 0 1757
50** 4 19 90 236 447 641 753 711 517 292 83 14 3787

**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 5/09 5/15 10/11 9/20 9/23 11/02 11/04
30 4/14 3/27 4/03 5/03 5/08 10/17 9/20 9/23 11/02 11/04
28 4/11 3/15 3/28 4/28 5/08 10/20 9/23 10/05 11/09 11/20
24 4/05 3/06 3/14 4/13 4/18 11/03 10/13 10/20 11/19 11/25
20 3/20 2/21 3/07 4/09 4/13 11/13 10/20 10/26 11/29 12/11
16 3/09 2/07 2/14 3/27 4/07 11/28 11/03 11/09 12/15 12/23

Length of Growing Season (Days)

Derived from 1971-2000 Averages

Temp °F Median Shortest 10% 90% Longest
32 172 139 152 186 208
30 181 140 167 205 208
28 194 150 171 212 250
24 214 189 196 241 259
20 234 194 210 258 271
16 264 222 233 286 300

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