Precipitation Summary
Station: 119002 WATERLOO, IL
1971-2000 NCDC Normals
| Element | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Ann |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Prec. (in) | 2.32 | 2.40 | 3.73 | 4.16 | 4.04 | 4.01 | 4.25 | 3.13 | 3.41 | 3.05 | 4.21 | 3.40 | 42.11 |
Precipitation Extremes
Period of Record: 1911-2006
| Month | High (in) | Year | Low (in) | Year | 1-Day Max (in) |
Date |
|---|---|---|---|---|---|---|
| Jan | 9.72 | 1916 | 0.07 | 2003 | 3.35 | 01-12-1916 |
| Feb | 5.28 | 1985 | 0.08 | 1917 | 3.00 | 02-01-1988 |
| Mar | 11.15 | 1945 | 0.50 | 1941 | 3.18 | 03-28-1977 |
| Apr | 12.81 | 1996 | 0.82 | 1955 | 6.79 | 04-29-1996 |
| May | 13.25 | 1995 | 0.18 | 1914 | 3.70 | 05-08-1961 |
| Jun | 10.08 | 2000 | 0.22 | 1991 | 5.41 | 06-11-1938 |
| Jul | 9.80 | 1958 | 0.07 | 2002 | 5.32 | 07-28-1979 |
| Aug | 12.38 | 1915 | 0.19 | 1930 | 7.03 | 08-20-1915 |
| Sep | 9.45 | 1984 | 0.00 | 2004 | 5.08 | 09-18-1986 |
| Oct | 11.79 | 1919 | 0.32 | 1952 | 6.24 | 10-26-1919 |
| Nov | 13.59 | 1985 | 0.39 | 1949 | 5.96 | 11-02-1972 |
| Dec | 9.34 | 1987 | 0.11 | 1955 | 3.80 | 12-10-1971 |
| Annual | 52.73 | 1973 | 20.04 | 1953 | 7.03 | 08-20-1915 |
| Winter | 17.19 | 1950 | 2.60 | 1954 | 3.80 | 12-10-1971 |
| Spring | 22.21 | 1945 | 3.78 | 1914 | 6.79 | 04-29-1996 |
| Summer | 24.47 | 1915 | 3.20 | 1930 | 7.03 | 08-20-1915 |
| Fall | 20.36 | 1984 | 2.31 | 1999 | 6.24 | 10-26-1919 |
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 | 7.5 | 4.8 | 1.3 | 0.5 |
| Feb | 6.8 | 4.5 | 1.5 | 0.6 |
| Mar | 9.9 | 7.1 | 2.7 | 0.8 |
| Apr | 10.4 | 7.4 | 2.5 | 1.1 |
| May | 10.4 | 7.2 | 2.9 | 1.0 |
| Jun | 9.2 | 6.4 | 2.8 | 1.0 |
| Jul | 8.0 | 5.8 | 2.6 | 1.4 |
| Aug | 7.4 | 5.3 | 2.0 | 0.9 |
| Sep | 7.0 | 4.7 | 2.0 | 0.9 |
| Oct | 8.2 | 5.4 | 2.2 | 0.8 |
| Nov | 9.5 | 6.7 | 2.6 | 1.0 |
| Dec | 8.2 | 5.7 | 2.4 | 1.0 |
| Annual | 102.7 | 71.1 | 27.6 | 10.9 |
| Winter | 22.5 | 14.9 | 5.1 | 2.1 |
| Spring | 30.7 | 21.7 | 8.1 | 2.9 |
| Summer | 24.7 | 17.6 | 7.5 | 3.2 |
| Fall | 24.6 | 16.7 | 6.8 | 2.7 |
Temperature Summary
Station 119002 WATERLOO, IL
1971-2000 NCDC Normals
| Element | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Ann |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| High °F | 37.6 | 44.0 | 54.8 | 66.0 | 75.6 | 84.4 | 88.5 | 86.9 | 79.9 | 68.6 | 54.3 | 42.0 | 65.2 |
| Low °F | 20.3 | 25.1 | 35.1 | 44.6 | 54.7 | 63.8 | 68.1 | 66.2 | 58.6 | 47.0 | 36.2 | 25.1 | 45.4 |
| Mean °F | 29.0 | 34.6 | 45.0 | 55.3 | 65.2 | 74.1 | 78.3 | 76.6 | 69.3 | 57.8 | 45.3 | 33.6 | 55.3 |
| HDD | 1118 | 853 | 621 | 306 | 110 | 6 | 0 | 3 | 41 | 250 | 595 | 976 | 4879 |
| CDD | 0 | 0 | 0 | 15 | 114 | 279 | 412 | 361 | 168 | 27 | 1 | 0 | 1377 |
HDD – heating degree days (base 65F); CDD – cooling degree days (base 65F)
Temperature Extremes
Period of Record: 1948-2000
| Month | High Mean °F |
Year | Low Mean °F |
Year | 1-Day Max °F |
Date | 1-Day Min °F |
Date |
|---|---|---|---|---|---|---|---|---|
| Jan | 41.3 | 1990 | 15.5 | 1977 | 75 | 01-23-1967 | -16 | 01-17-1977 |
| Feb | 42.7 | 1976 | 22.1 | 1978 | 83 | 02-13-1962 | -12 | 02-03-1996 |
| Mar | 52.9 | 1973 | 36.5 | 1984 | 88 | 03-29-1985 | 0 | 03-02-1980 |
| Apr | 63.4 | 1948 | 49.3 | 1983 | 93 | 04-26-1989 | 21 | 04-10-1996 |
| May | 74.5 | 1962 | 60.4 | 1976 | 95 | 05-27-1978 | 30 | 05-03-1976 |
| Jun | 78.5 | 1971 | 69.9 | 1982 | 103 | 06-25-1988 | 42 | 06-01-1972 |
| Jul | 82.9 | 1966 | 74.7 | 1967 | 106 | 07-12-1966 | 47 | 07-06-1972 |
| Aug | 81.8 | 1983 | 70.8 | 1992 | 107 | 08-21-1962 | 45 | 08-13-1964 |
| Sep | 74.2 | 1998 | 63.3 | 1974 | 102 | 09-14-1971 | 34 | 09-23-1983 |
| Oct | 70.5 | 1963 | 51.2 | 1976 | 94 | 10-11-1963 | 22 | 10-25-1981 |
| Nov | 53.5 | 1999 | 36.9 | 1976 | 89 | 11-03-1987 | 3 | 11-30-1964 |
| Dec | 43.7 | 1965 | 20.2 | 1983 | 75 | 12-03-1970 | -18 | 12-22-1989 |
| Annual | 60.1 | 1961 | 53.0 | 1979 | 107 | 08-21-1962 | -18 | 12-22-1989 |
| Winter | 37.3 | 2000 | 24.8 | 1978 | 83 | 02-13-1962 | -18 | 12-22-1989 |
| Spring | 60.2 | 1977 | 50.9 | 1984 | 95 | 05-27-1978 | 0 | 03-02-1980 |
| Summer | 79.7 | 1980 | 72.8 | 1992 | 107 | 08-21-1962 | 42 | 06-01-1972 |
| Fall | 63.7 | 1963 | 52.2 | 1976 | 102 | 09-14-1971 | 3 | 11-30-1964 |
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 | 10.8 | 25.9 | 1.8 |
| Feb | 0.0 | 6.3 | 19.7 | 0.7 |
| Mar | 0.0 | 1.0 | 13.3 | 0.0 |
| Apr | 0.2 | 0.0 | 2.8 | 0.0 |
| May | 1.1 | 0.0 | 0.1 | 0.0 |
| Jun | 8.1 | 0.0 | 0.0 | 0.0 |
| Jul | 14.8 | 0.0 | 0.0 | 0.0 |
| Aug | 11.5 | 0.0 | 0.0 | 0.0 |
| Sep | 4.6 | 0.0 | 0.0 | 0.0 |
| Oct | 0.2 | 0.0 | 2.3 | 0.0 |
| Nov | 0.0 | 0.7 | 11.4 | 0.0 |
| Dec | 0.0 | 5.8 | 22.8 | 0.8 |
| Annual | 41.0 | 24.7 | 97.5 | 3.4 |
| Winter | 0.0 | 23.0 | 68.4 | 3.4 |
| Spring | 1.3 | 1.0 | 16.1 | 0.0 |
| Summer | 34.4 | 0.0 | 0.0 | 0.0 |
| Fall | 4.9 | 0.7 | 13.3 | 0.0 |
Snowfall Summary
Station: 119002 WATERLOO, IL
1971-2000 Averages
| Element | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Ann |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Snow (in) | 4.7 | 3.0 | 1.9 | 0.7 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 1.3 | 3.0 | 14.6 |
Snowfall Extremes
Period of Record: 1911-2006
| Month | High (in) | Year | 1-Day Max (in) | Date |
|---|---|---|---|---|
| Jan | 18.9 | 1982 | 15.0 | 01-31-1982 |
| Feb | 18.5 | 1993 | 11.0 | 02-26-1993 |
| Mar | 23.1 | 1960 | 8.0 | 03-03-1960 |
| Apr | 9.0 | 1971 | 7.5 | 04-06-1971 |
| May | 0.0 | – | – | – |
| Jun | 0.0 | – | – | – |
| Jul | 0.0 | – | – | – |
| Aug | 0.0 | – | – | – |
| Sep | 0.0 | – | – | – |
| Oct | 0.0 | – | – | – |
| Nov | 12.0 | 1980 | 9.0 | 11-27-1980 |
| Dec | 17.9 | 1973 | 12.0 | 12-20-1973 |
| Season (Jul-Jun) | 40.4 | 1959-1960 | 15.0 | 01-31-1982 |
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 | 1.9 | 0.9 | 0.5 | 0.1 |
| Feb | 1.9 | 0.9 | 0.5 | 0.1 |
| Mar | 1.1 | 0.7 | 0.4 | 0.1 |
| Apr | 0.2 | 0.2 | 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 | 0.6 | 0.4 | 0.3 | 0.1 |
| Dec | 1.5 | 1.0 | 0.6 | 0.1 |
| Annual | 8.1 | 4.6 | 2.9 | 0.6 |
Growing Season Summary
Station: 119002 WATERLOO, 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 | 37 | 84 | 240 | 477 | 787 | 1030 | 1187 | 1134 | 881 | 556 | 237 | 66 | 6685 |
| 45 | 15 | 43 | 148 | 342 | 633 | 880 | 1033 | 979 | 731 | 409 | 147 | 31 | 5374 |
| 50 | 5 | 18 | 84 | 224 | 481 | 730 | 878 | 824 | 583 | 278 | 82 | 13 | 4192 |
| 55 | 1 | 5 | 42 | 132 | 334 | 580 | 723 | 669 | 438 | 170 | 40 | 4 | 3140 |
| 60 | 0 | 1 | 18 | 68 | 205 | 431 | 569 | 514 | 302 | 87 | 15 | 0 | 2215 |
| 50** | 22 | 52 | 142 | 282 | 498 | 700 | 815 | 775 | 577 | 336 | 132 | 38 | 4358 |
**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 | 4/10 | 3/24 | 3/25 | 4/22 | 5/04 | 10/20 | 10/01 | 10/04 | 11/05 | 11/10 |
| 30 | 4/07 | 3/18 | 3/23 | 4/19 | 5/04 | 10/27 | 10/09 | 10/12 | 11/07 | 11/12 |
| 28 | 4/05 | 3/07 | 3/16 | 4/11 | 4/19 | 11/06 | 10/11 | 10/20 | 12/01 | 12/09 |
| 24 | 3/20 | 3/06 | 3/09 | 4/09 | 4/11 | 11/16 | 10/23 | 11/03 | 12/03 | 12/22 |
| 20 | 3/09 | 2/03 | 2/08 | 3/25 | 3/27 | 11/24 | 11/02 | 11/08 | 12/19 | 12/22 |
| 16 | 2/18 | 1/10 | 2/03 | 3/12 | 3/25 | 12/09 | 11/02 | 11/10 | 12/22 | 1/12 |
Length of Growing Season (Days)
Derived from 1971-2000 Averages
| Temp °F | Median | Shortest | 10% | 90% | Longest |
|---|---|---|---|---|---|
| 32 | 193 | 160 | 175 | 215 | 226 |
| 30 | 207 | 167 | 187 | 218 | 235 |
| 28 | 215 | 191 | 197 | 247 | 269 |
| 24 | 239 | 213 | 218 | 265 | 284 |
| 20 | 265 | 228 | 238 | 295 | 311 |
| 16 | 286 | 237 | 254 | 317 | 348 |
Copyright 2007 Illinois State Water Survey
Last Modified: September 11, 2007