Alabama |
32 |
813 |
July 19 - 20, 1997 (Dauphin Island #2 ) |
Although higher amounts have been observed in other states, the 32.52 inches of rainfall that was observed in 24-hrs over July 19-20, 1997 at Dauphin Island Sea Lab in conjunction with Hurricane Danny is the greatest 24-hr rainfall that has been directly observed at an officially established observation station within the coterminous United States.
|
Alaska |
15 |
381 |
October 10, 1986 (Seward Airport ) |
The previously-listed state record of 15.2 inches at Angoon on October 12, 1982 was determined to be invalid by the SCEC, based largely on analysis that resulted in this Bulletin of the American Meteorological Society article.
|
Arizona |
11 |
279 |
September 4 - 5, 1970 (Workman Creek 1 ) |
|
Arkansas |
14 |
356 |
December 3, 1982 (Big Fork 1 Sse ) |
|
California |
25 |
635 |
January 22 - 23, 1943 (Hoegees Fc 60 A ) |
Hourly precipitation values for Hoegee's Campground (in the mountains outside Los Angeles) indicate the greatest 24-hour rainfall occurred between 1:00 AM on January 22nd to 1:00 AM on January 23rd. During that period, the storm delivered 25.83 inches (corrected from previous reports of 26.12 inches). A detailed post-storm report was produced by the Weather Bureau.
|
Colorado |
11 |
279 |
September 12, 2013 (Usgs Rod & Gun (ft. Carson) ) |
Had a 9 AM to 9 AM observing period been used ending at 9 AM on September 13th, that the measurement would have been 12.46". However, the SCEC chose to confirm the calendar-day value as the official record. In either case, the previously acknolwedged record of 11.08" at Holly on June 17, 1965 was superseded.
|
Connecticut |
12 |
305 |
August 19, 1955 (Burlington ) |
|
Delaware |
8 |
203 |
July 13, 1975 (Dover ) |
|
Florida |
23 |
584 |
November 11 - 12, 1980 (Key West Intl Airport ) |
The previously reported extreme of 38.70 inches at Yankeetown on September 5, 1950 is an estimated depth of rainfall calculated as part of a post-storm survey of Hurricane Easy (Cedar Keys Hurricane). Value has historically been considered reasonably accurate (and even an underestimate of actual rain fall), but as an estimate cannot be considered an official observation from a reliable precipitation gauge.
|
Georgia |
21 |
533 |
July 6, 1994 (Americus ) |
|
Hawaii |
38 |
965 |
January 24 - 25, 1956 (Kilauea 1134 ) |
The 38.00 inches in 24-hrs at Kilauea Sugar Co. Plantation (Kauai) on January 24-25, 1956 is an estimate, but is listed as the record because it was obtained from a reliable rain gauge and is deemed conservative by an inch or more (that is, the 12-inch gauge was overflowing when it was emptied for the first time). Storm reports indicated 41.90 inches fell over period 9 AM 1/24/56 to 3 PM 1/25/56 (including 6-inches in 30 minutes and 12 inches in the first hour). The greatest accurately observed 24-hr precipitation is 31.95 inches at Honomu (Hawaii) on February 20, 1918. More information on the January 24-25, 1956 Kilauea storm rain fall can be found on page 10 of the Weather Bureau's 1961 "Climate of the States: Hawaii (Climatography of the United States No. 60-51)".
|
Idaho |
7 |
178 |
November 23, 1909 (Rattlesnake Creek ) |
|
Illinois |
16 |
406 |
July 18, 1996 (Aurora ) |
|
Indiana |
10 |
254 |
August 6, 1905 (Princeton 1 W ) |
|
Iowa |
13 |
330 |
June 14, 1998 (Atlantic 1 Ne ) |
Previously reported record of 16.70 inches in Decatur Co. on August 5-6, 1959 is likely valid, but was estimated from a post-event survey observation. A 13.52 inch observation was made at Atlantic 5SW on June 14, 1998, but it is likely that the observation covered more than a 24-hr period.
|
Kansas |
0 |
0 |
(Under Review ) |
The previously posted value of 13.53" was discovered to be in error. An investigation to determine the legitimate record is underway.
|
Kentucky |
10 |
254 |
March 1, 1997 (Louisville Wfo ) |
Historical value was examined retroactively and found to be valid and exceeded prior stated record.
|
Louisiana |
22 |
559 |
August 28 - 29, 1962 (Hackberry 8 Ssw ) |
|
Maine |
13 |
330 |
October 20 - 21, 1996 (Portland Jetport ) |
|
Maryland |
14 |
356 |
July 26 - 27, 1897 (Jewell ) |
|
Massachusetts |
18 |
457 |
August 18 - 19, 1955 (Westfield ) |
|
Michigan |
9 |
229 |
August 31, 1914 (Bloomingdale ) |
|
Minnesota |
15 |
381 |
August 19, 2007 (Hokah Wwtp ) |
|
Mississippi |
15 |
381 |
July 9, 1968 (Columbus 4 Ese ) |
|
Missouri |
18 |
457 |
July 20, 1965 (Edgerton ) |
|
Montana |
11 |
279 |
June 20, 1921 (Springbrook ) |
|
Nebraska |
13 |
330 |
July 8 - 9, 1950 (York ) |
|
Nevada |
7 |
178 |
October 20, 2004 (Mt. Charleston Fire Station ) |
|
New Hampshire |
11 |
279 |
October 20 - 21, 1996 (Mount Washington ) |
|
New Jersey |
14 |
356 |
August 19 - 20, 1939 (Tuckerton 2 Ne ) |
|
New Mexico |
11 |
279 |
May 18 - 19, 1955 (Lake Maloya ) |
|
New York |
13 |
330 |
August 12 - 13, 2014 (Islip-li Macarthur Ap ) |
|
North Carolina |
22 |
559 |
July 15 - 16, 1916 (Altapass ) |
|
North Dakota |
8 |
203 |
June 29, 1975 (Litchville 2nw ) |
|
Ohio |
10 |
254 |
August 7 - 8, 1995 (Lockington Dam (nr. Sidney, Shelby Co. Oh) ) |
Value is published in the August 1995 Storm Data publication and is from a reliable gauge. Higher 24-hr amounts may have occurred in conjunction with a line of severe storms that impacted Northwest Ohio on July 4-5, 1969.
|
Oklahoma |
15 |
381 |
October 11, 1973 (Enid ) |
|
Oregon |
11 |
279 |
November 6, 2006 (Nehalem 9 Ne ) |
|
Pennsylvania |
13 |
330 |
June 22, 1972 (York 3 Ssw Pump Stn ) |
Arguably the greatest 24-hour rainfall on record outside of the tropics occurred around Smethport, PA on July 17, 1942. A post-event survey by the Weather Bureau provided a widely accepted maximum storm rainfall of 34.50 inches within a 12 hour period, of which an estimated 30.60 inches fell in just 6 hours. However, the greatest observed 24-hr rain fall for Pennsylvania occurred in conjunction with Hurricane Agnes in 1972.
|
Puerto Rico |
23 |
584 |
October 7, 1985 (Toro Negro Forest ) |
Value was observed during the passage of Tropical Storm Isabel (October 4-8, 1985).
|
Rhode Island |
12 |
305 |
September 16 - 17, 1932 (Westerly 1 W ) |
|
South Carolina |
14 |
356 |
September 16, 1999 (Myrtle Beach ) |
Previously listed record of 17.00 inches at Antreville on Augst 27, 1995 (Tropical Storm Jerry) was incongruent with other observations in the area, and all reliable evidence pointed to a much smaller 24-hr value. The 14.80 inches observed at Myrtle Beach on September 16, 1999 is a result of Hurricane Floyd.
|
South Dakota |
8 |
203 |
May 6, 2007 (Groton ) |
The reported value was evaluated by the State Climate Extremes Committee. Greater amounts have fallen in 24 hours or less across SD, but were not observed by reliable precipitation measurement gauges. A survey after the June 9, 1972 Black Hills flood indicated rainfall up to 15 inches in 6 hours may have occurred near Keystone. On June 13-14, 1976 up to 10 inches of rain may have fallen over the Black Hills, while on June 14, 1996 a near-stationary thunderstorm produced an estimated 14 inches of rain between Sturgis and Hereford. On August 17, 2007 an estimated 10.5 inches of rain fell west of Hermosa. Slow moving thunderstorms on May 8, 2018 produced large storm totals across parts of SD including an unofficial 24-hour report measuring 13.15 inches northwest of Long Lake.
|
Tennessee |
13 |
330 |
September 13, 1982 (Milan Exp Stn ) |
|
Texas |
42 |
1067 |
July 25 - 26, 1979 (Alvin ) |
The 24-hour rainfall of 42.00 inches was reported from an observer 8.5 miles west of Alvin, Texas between 7 AM July 25th and 7 AM July 26th, 1979 in conjunction with Tropical Storm Claudette. Observer reported that the 10-inch gauge was overflowing at his 1 AM reading, and so the 42 inches may be underreported by at least 3 inches. This 42.00-in rainfall exceeds any observed 24-hr precipitation value for the United States. 43.00 inches of rain in this storm is acknowledged as the United States national record 24-hr precipitation amount, but that value appears to have been estimated in a post-storm survey and is therefore not listed here.
|
Utah |
5 |
127 |
February 1, 1963 (Deer Creek Dam ) |
A value of 8.40 inches was reported as part of a post-flash flood survey conducted by the National Weather Service at North Odgen on September 7-8, 1991.
|
Vermont |
9 |
229 |
September 17, 1999 (Mount Mansfield ) |
|
Virgin Islands (U.S.) |
20 |
508 |
September 4, 1979 (Annas Hope ) |
|
Virginia |
14 |
356 |
September 16, 1999 (Williamsburg 2 N ) |
Storm Data (Vol. 11, No. 8) reports associated with Hurricane Camille (August 1969) indicate "... substantiated amounts up to 31 inches ... falling mainly in Nelson and adjacent counties ...." The 14.28 inches at Williamsburg fell in conjunction with Hurricane Floyd.
|
Washington |
14 |
356 |
November 23 - 24, 1986 (Mount Mitchell #2 ) |
|
West Virginia |
12 |
305 |
June 18, 1949 (Brushy Run ) |
It is widely accepted that the greatest precipitation in a 24 hr period for West Virginia was an estimated 19.00 inches that reportedly fell in 2 hrs and 10 minutes on July 18, 1889 at Rockport during a cloudburst that caused Tygart Creek to rise 22 feet in one hour. However, this value has not been confirmed.
|
Wisconsin |
11 |
279 |
June 24, 1946 (Mellen 4 Ne ) |
|
Wyoming |
6 |
152 |
August 1, 1985 (Cheyenne Wsfo Ap ) |
|