Precipitation Summary
Station: 111577 CHICAGO MIDWAY AIRPORT 3SW, IL
1971-2000 NCDC Normals
| Element | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Ann |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Prec. (in) | 1.95 | 1.78 | 2.83 | 3.82 | 3.86 | 4.16 | 3.82 | 3.91 | 3.45 | 2.79 | 3.22 | 2.76 | 38.35 |
Precipitation Extremes
Period of Record: 1928-2006
| Month | High (in) | Year | Low (in) | Year | 1-Day Max (in) |
Date |
|---|---|---|---|---|---|---|
| Jan | 5.32 | 2005 | 0.13 | 1981 | 2.76 | 01-12-1960 |
| Feb | 6.76 | 1997 | 0.25 | 1969 | 3.25 | 02-21-1997 |
| Mar | 5.37 | 1976 | 0.33 | 1958 | 2.50 | 03-31-1929 |
| Apr | 8.33 | 1947 | 0.45 | 1971 | 3.83 | 04-18-1975 |
| May | 7.59 | 1945 | 0.25 | 1992 | 3.30 | 05-11-1966 |
| Jun | 13.03 | 1993 | 0.78 | 1956 | 4.64 | 06-13-1976 |
| Jul | 10.29 | 1996 | 0.31 | 1936 | 6.16 | 07-12-1957 |
| Aug | 9.95 | 1987 | 0.76 | 1996 | 3.90 | 08-26-1987 |
| Sep | 14.17 | 1961 | 0.01 | 1979 | 4.16 | 09-11-2000 |
| Oct | 12.06 | 1954 | 0.20 | 1964 | 3.95 | 10-03-1954 |
| Nov | 7.63 | 1985 | 0.55 | 1976 | 3.49 | 11-10-1995 |
| Dec | 7.21 | 1982 | 0.30 | 1962 | 2.78 | 12-02-1982 |
| Annual | 49.64 | 1993 | 21.32 | 1943 | 6.16 | 07-12-1957 |
| Winter | 13.79 | 1950 | 1.45 | 1931 | 3.25 | 02-21-1997 |
| Spring | 17.02 | 1983 | 2.79 | 1934 | 3.83 | 04-18-1975 |
| Summer | 21.69 | 1993 | 4.58 | 2005 | 6.16 | 07-12-1957 |
| Fall | 19.32 | 1961 | 2.07 | 1956 | 4.16 | 09-11-2000 |
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 | 11.2 | 5.0 | 0.9 | 0.3 |
| Feb | 8.9 | 4.6 | 0.9 | 0.1 |
| Mar | 11.7 | 6.6 | 1.8 | 0.4 |
| Apr | 11.6 | 7.2 | 2.4 | 0.9 |
| May | 11.0 | 7.1 | 2.5 | 0.8 |
| Jun | 10.3 | 6.4 | 2.9 | 1.2 |
| Jul | 9.5 | 6.1 | 2.4 | 1.0 |
| Aug | 9.6 | 6.3 | 2.7 | 1.2 |
| Sep | 8.9 | 5.5 | 2.1 | 0.8 |
| Oct | 9.7 | 5.6 | 1.8 | 0.6 |
| Nov | 11.5 | 6.7 | 2.0 | 0.6 |
| Dec | 11.3 | 5.3 | 1.7 | 0.5 |
| Annual | 125.1 | 72.5 | 24.1 | 8.4 |
| Winter | 31.4 | 15.0 | 3.5 | 0.9 |
| Spring | 34.2 | 21.0 | 6.7 | 2.1 |
| Summer | 29.4 | 18.9 | 8.0 | 3.3 |
| Fall | 30.1 | 17.7 | 5.9 | 2.0 |
Temperature Summary
Station 111577 CHICAGO MIDWAY AP 3SW, IL
1971-2000 NCDC Normals
| Element | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Ann |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| High °F | 30.7 | 36.1 | 47.4 | 59.2 | 71.3 | 80.8 | 84.7 | 82.3 | 75.1 | 63.2 | 48.0 | 35.6 | 59.5 |
| Low °F | 16.2 | 21.3 | 30.6 | 40.2 | 50.9 | 60.7 | 66.3 | 65.0 | 56.7 | 44.9 | 33.6 | 22.2 | 42.4 |
| Mean °F | 23.5 | 28.7 | 39.0 | 49.7 | 61.1 | 70.8 | 75.5 | 73.7 | 65.9 | 54.1 | 40.8 | 28.9 | 51.0 |
| HDD | 1288 | 1017 | 805 | 462 | 203 | 28 | 4 | 11 | 67 | 352 | 726 | 1120 | 6083 |
| CDD | 0 | 0 | 0 | 4 | 82 | 199 | 330 | 279 | 95 | 12 | 0 | 0 | 1001 |
HDD – heating degree days (base 65F); CDD – cooling degree days (base 65F)
Temperature Extremes
Period of Record: 1928-2006
| Month | High Mean °F |
Year | Low Mean °F |
Year | 1-Day Max °F |
Date | 1-Day Min °F |
Date |
|---|---|---|---|---|---|---|---|---|
| Jan | 36.5 | 2006 | 10.1 | 1977 | 67 | 01-25-1950 | -25 | 01-20-1985 |
| Feb | 39.7 | 1998 | 13.6 | 1936 | 75 | 02-27-1976 | -20 | 02-09-1933 |
| Mar | 48.6 | 1945 | 26.4 | 1960 | 86 | 03-29-1986 | -7 | 03-08-1943 |
| Apr | 57.0 | 1955 | 41.7 | 1950 | 92 | 04-30-1942 | 10 | 04-07-1982 |
| May | 69.3 | 1977 | 53.0 | 1935 | 102 | 05-31-1934 | 28 | 05-12-1981 |
| Jun | 76.4 | 1933 | 63.0 | 1928 | 107 | 06-01-1934 | 35 | 06-04-1945 |
| Jul | 81.3 | 1999 | 70.6 | 1967 | 107 | 07-11-1936 | 46 | 07-05-1972 |
| Aug | 81.3 | 1995 | 69.2 | 1967 | 103 | 08-22-1936 | 43 | 08-29-1965 |
| Sep | 71.7 | 2005 | 60.4 | 1949 | 102 | 09-15-1939 | 29 | 09-28-1942 |
| Oct | 64.3 | 1963 | 48.2 | 1987 | 94 | 10-06-1963 | 20 | 10-20-1930 |
| Nov | 50.3 | 2001 | 32.8 | 1976 | 81 | 11-01-1950 | -3 | 11-28-1930 |
| Dec | 37.1 | 1982 | 16.5 | 1983 | 71 | 12-03-1970 | -20 | 12-24-1983 |
| Annual | 55.0 | 1998 | 40.0 | 1929 | 107 | 06-01-1934 | -25 | 01-20-1985 |
| Winter | 34.2 | 2002 | 18.5 | 1979 | 75 | 02-27-1976 | -25 | 01-20-1985 |
| Spring | 56.2 | 1977 | 44.1 | 1947 | 102 | 05-31-1934 | -7 | 03-08-1943 |
| Summer | 78.2 | 1995 | 69.8 | 1945 | 107 | 06-01-1934 | 35 | 06-04-1945 |
| Fall | 59.2 | 1963 | 48.6 | 1976 | 102 | 09-15-1939 | -3 | 11-28-1930 |
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 | 16.3 | 28.1 | 4.6 |
| Feb | 0.0 | 10.7 | 22.9 | 1.8 |
| Mar | 0.0 | 3.4 | 18.4 | 0.0 |
| Apr | 0.1 | 0.1 | 5.3 | 0.0 |
| May | 1.3 | 0.0 | 0.4 | 0.0 |
| Jun | 4.6 | 0.0 | 0.0 | 0.0 |
| Jul | 8.4 | 0.0 | 0.0 | 0.0 |
| Aug | 5.0 | 0.0 | 0.0 | 0.0 |
| Sep | 1.9 | 0.0 | 0.0 | 0.0 |
| Oct | 0.1 | 0.0 | 2.0 | 0.0 |
| Nov | 0.0 | 1.9 | 13.7 | 0.0 |
| Dec | 0.0 | 10.0 | 25.3 | 1.8 |
| Annual | 21.4 | 42.6 | 116.1 | 8.3 |
| Winter | 0.0 | 37.1 | 76.2 | 8.2 |
| Spring | 1.4 | 3.5 | 24.2 | 0.0 |
| Summer | 17.9 | 0.0 | 0.0 | 0.0 |
| Fall | 2.0 | 1.8 | 15.4 | 0.0 |
Snowfall Summary
Station: 111577 CHICAGO MIDWAY AP 3SW, IL
1971-2000 Averages
| Element | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Ann |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Snow (in) | 12.9 | 10.3 | 6.0 | 1.4 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.1 | 2.3 | 10.1 | 43.1 |
Snowfall Extremes
Period of Record: 1928-2006
| Month | High (in) | Year | 1-Day Max (in) | Date |
|---|---|---|---|---|
| Jan | 40.4 | 1979 | 17.6 | 01-02-1999 |
| Feb | 26.2 | 1994 | 11.0 | 02-07-1933 |
| Mar | 24.1 | 1930 | 16.5 | 03-25-1930 |
| Apr | 12.2 | 1982 | 9.8 | 04-05-1982 |
| May | 3.7 | 1940 | 3.2 | 05-01-1940 |
| Jun | 0.0 | – | – | – |
| Jul | 0.0 | – | – | – |
| Aug | 0.0 | – | – | – |
| Sep | 0.0 | – | – | – |
| Oct | 4.4 | 1967 | 3.0 | 10-20-1952 |
| Nov | 13.0 | 1951 | 8.0 | 11-06-1951 |
| Dec | 41.3 | 2000 | 14.5 | 12-11-2000 |
| Season (Jul-Jun) | 93.3 | 1978-1979 | 17.6 | 01-02-1999 |
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 | 6.2 | 3.0 | 1.9 | 0.4 |
| Feb | 6.2 | 3.0 | 1.9 | 0.4 |
| Mar | 4.5 | 1.9 | 1.0 | 0.2 |
| Apr | 1.0 | 0.3 | 0.1 | 0.1 |
| May | 0.1 | 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 | 0.0 | 0.0 | 0.0 |
| Nov | 2.7 | 0.8 | 0.4 | 0.0 |
| Dec | 7.2 | 2.8 | 1.4 | 0.4 |
| Annual | 30.5 | 12.9 | 6.9 | 1.5 |
Growing Season Summary
Station: 111577 CHICAGO MIDWAY AP 3SW, 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 | 23 | 115 | 317 | 656 | 927 | 1104 | 1053 | 789 | 449 | 137 | 25 | 5587 |
| 45 | 2 | 8 | 65 | 200 | 503 | 777 | 950 | 898 | 639 | 307 | 72 | 11 | 4423 |
| 50 | 0 | 2 | 34 | 112 | 357 | 627 | 795 | 743 | 491 | 188 | 35 | 4 | 3385 |
| 55 | 0 | 0 | 15 | 57 | 230 | 478 | 641 | 588 | 346 | 102 | 14 | 1 | 2473 |
| 60 | 0 | 0 | 6 | 26 | 133 | 334 | 487 | 434 | 219 | 46 | 4 | 0 | 1691 |
| 50** | 3 | 12 | 66 | 174 | 390 | 611 | 760 | 722 | 496 | 244 | 64 | 11 | 3549 |
**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 | 4/17 | 3/26 | 4/06 | 5/10 | 5/16 | 10/23 | 10/01 | 10/07 | 11/12 | 11/19 |
| 30 | 4/10 | 3/23 | 3/27 | 4/23 | 5/12 | 11/02 | 10/02 | 10/17 | 11/13 | 11/19 |
| 28 | 4/08 | 3/18 | 3/22 | 4/17 | 5/12 | 11/04 | 10/02 | 10/21 | 11/20 | 11/27 |
| 24 | 3/24 | 3/08 | 3/13 | 4/10 | 4/19 | 11/13 | 10/24 | 11/03 | 12/03 | 12/21 |
| 20 | 3/16 | 2/12 | 2/24 | 4/06 | 4/09 | 11/22 | 10/24 | 11/07 | 12/11 | 12/21 |
| 16 | 3/03 | 1/27 | 2/09 | 4/01 | 4/07 | 12/03 | 11/02 | 11/16 | 12/20 | 12/24 |
Length of Growing Season (Days)
Derived from 1971-2000 Averages
| Temp °F | Median | Shortest | 10% | 90% | Longest |
|---|---|---|---|---|---|
| 32 | 187 | 143 | 157 | 215 | 226 |
| 30 | 205 | 160 | 179 | 221 | 228 |
| 28 | 212 | 164 | 193 | 239 | 251 |
| 24 | 234 | 207 | 213 | 257 | 281 |
| 20 | 250 | 222 | 229 | 283 | 285 |
| 16 | 275 | 222 | 240 | 297 | 324 |
Copyright 2007 Illinois State Water Survey
Last Modified: September 11, 2007