| Rank | Precipitation | Month |
|---|---|---|
| 1 | 6.5 inches | May 1978 |
| 2 | 6.3 inches | May 1995 |
| 3 | 5.6 inches | May 1971 |
| 4 | 5.1 inches | September 1923 |
| 5 | 5.1 inches | May 1935 |
| 6 | 4.8 inches | May 1991 |
| 7 | 4.7 inches | June 2003 |
| 8 | 4.6 inches | October 1998 |
| 9 | 4.5 inches | April 1922 |
| 10 | 4.5 inches | September 1915 |
| 11 | 4.4 inches | April 1933 |
| 12 | 4.3 inches | May 2008 |
| 13 | 4.2 inches | October 1994 |
| 14 | 4.2 inches | May 1922 |
| 15 | 4.2 inches | June 1982 |
| 16 | 4.1 inches | May 1929 |
| 17 | 4.1 inches | June 1986 |
| 18 | 4.1 inches | May 1917 |
| 19 | 4.0 inches | April 1932 |
| 20 | 3.9 inches | May 1920 |