According to the rainfall reports through yesterday (6/29), the statewide average precipitation is now 9.37 inches.
- The old record for June was 8.27 inches set in 1902.
- The current 9.37 inches beats the old record by 1.10 inches.
- The current 9.37 inches is 5.17 inches above the June average of 4.20 inches.
- The current 9.37 inches make this the second wettest month in Illinois history.
- Only September 1926 was a wetter month at 9.62 inches.
- Statewide records for Illinois go back to 1895.
The statewide average precipitation is based on records from about 650 rain gauges across the state. A majority of the reports come from two networks with trained volunteers and standardized equipment and procedures. One network is called CoCoRaHS and the other is the NWS Cooperative Observer Network or COOP for short. These dedicated observers give timely and accurate information with outstanding coverage across the state.
Tomorrow we will be able to do the calculation through June 30.
The statewide average for June is now 8.97 inches. That is based on rainfall data collected around the state through yesterday. I’m sure we will see that number move up as we include last night’s rainfall.
Right now June 2015 is the fourth wettest month on record for Illinois. If you look at the top 5 wettest months in Illinois history (below), all the other wet months were in the fall.
- September 1926 at 9.62 inches
- October 1941 at 9.06 inches
- November 1985 at 9.05 inches
- June 2015 at 8.97 inches
- September 1911 at 8.96 inches
Illinois now has its wettest June on record with a statewide average rainfall of 8.91 inches as of June 27. More rain is expected through June 30.
- 2015 with 8.91 inches (as of 6/27)
- 1902 with 8.27 inches
- 2010 with 7.71 inches
- 1998 with 7.64 inches
- 2000 with 7.34 inches
Statewide records for Illinois go back to 1895.
According to the latest data, the statewide rainfall total for June in Illinois is 8.12 inches, the second wettest June on record. The record is 8.27 inches set back in 1902.
In the map below, the areas in green are 5 to 8 inches of rain. The areas in blue are 8 to 11 inches.
The remains of Tropical Storm Bill moved through Texas and Oklahoma and up through the Midwest. As a result, it produced quite a bit of rain in southern Illinois.
While it is difficult to separate out the rainfall exclusively from Tropical Storm Bill, this radar-estimated rainfall image of the past 7 days shows the pattern. Areas in yellow and red received at least 3 inches of rainfall. The widespread areas in red south of Interstate 70 received in the neighborhood of 6 to 8 inches of rain.
Missouri, Indiana, Ohio, and Kentucky received significant rainfall as well.
Click to enlarge.