September 2026
Precipitation
During September 2026, Indiana’s average precipitation was slightly below normal, with a statewide monthly precipitation average of 91 percent normal. The overall monthly temperature average for Indiana was 71.5 degrees Fahrenheit or 5.5 degrees above normal.
Six of the nine climate divisions received much below or below normal precipitation for September (see Percent of Normal Precipitation Table). Climate Division 3 (NE) received the highest (165.0) percentage of normal precipitation for the month, while Climate Division 9 (SE) received the lowest (57.3) percentage.
Precipitation for the year to date (2026) ranges from 98.4% to 125.7% through September. Precipitation for the Water Year 2026 to date ranges from 92.6% to 108.3% through September. Over the 2-year period (from October 2024-September 2026), All nine climate divisions have received near normal or above normal precipitation ranging from 94.4% for Climate Division 3 (NE) to 110.9% for Climate Division 8 (SC).
The 12-month SPI indices show Climate Division 6 (EC) in the “very wet” category; climate divisions 1 (NE) and 2 (NC) in the “moderately wet” category; and the remaining climate divisions in the “near normal” category. The 6-month SPI indices show Climate Division 6 (EC) in the “extremely wet” category; climate divisions 1 (NW), 2 (NC), 3 (NE), 4 (WC), and 5 (C) in the “very wet” category; climate divisions 8 (SC) and 9 (SE) in the “moderately wet” category; and Climate Division 7 (SW) in the “near normal” category. The 3-month SPI indices show climate divisions 2 (NC) and 6 (EC) in the “very wet” category; climate divisions 1 (NW), 3 (NE), and 5 (C) in the “moderately wet”; and the remaining climate divisions in the “near normal” category. The 1-month SPI indices show Climate Division 1 (NE) in the “moderately wet” category; and the remaining climate divisions in the “near normal” category.
- Table of recent precipitation compared to normal for each climatic division of the state
- Standardized Precipitation Index (SPI) drought maps for the state for current month.
- Explanation of Standardized Precipitation Index (SPI)
U. S. Drought Monitor
For October 6, 2026, the U.S. Drought Monitor shows most of the far southern portions of Indiana experiencing “abnormally dry” conditions and no drought conditions for the rest of Indiana. The U.S. Seasonal Drought Outlook predicts no drought conditions through at least the end of December 2026.
Streamflow
In September 2026, ten of the twelve streams included in drought reporting since 1999 had above normal to significantly above normal stream flow. Muscatatuck River near Deputy had the lowest mean monthly flow at 16%, and the St. Marys River at Decatur had the highest mean monthly flow at 1670%.
Lake Michigan
On September 25, 2026, the Lake Michigan-Huron water level was 3 inches below the measurement taken on August 25, 2026, and 7 inches above the measurement taken on September 25, 2025. On September 25, 2026, the Michigan-Huron mean level was 579.04 feet, which is 29 inches above the lowest recorded monthly mean level for September set in 1964. A comparison of September monthly mean water levels to the long-term (1918-present) average shows Lakes Michigan-Huron water levels were about 1 inch below the average. All Lake Michigan-Huron data are referenced to the International Great Lakes Datum 1985.
The Lake Michigan-Huron water level is forecast by the U.S. Army Corps of Engineers to decrease 3 inches over the next month.
Reservoirs
On September 30, 2026, the water levels for all eight reservoirs monitored by the U.S. Army Corps of Engineers were at or above the normal pool elevation. The deviation from normal pool ranged from 0.0 feet (Cagles Mill) to +36.01 feet (Roush).
All the three reservoirs monitored by Citizens Water (Morse, Geist, and Eagle Creek) were above their respective normal pool elevations as of September 30, 2026. The deviation from normal pool ranged from +0.17 feet (Geist) to +0.51 feet (Eagle Creek).
Groundwater Levels
As of September 30, 2026, new water level data is available for all nine wells currently monitored. Data indicates that water level is above normal for four of the nine wells: Laporte 9, Fulton 7, Vigo 7, and Morgan 4. Data indicates that the water level is near normal for Randolph 3, Posey 3, and Harrison 8; and water level remains well below normal for LaGrange 2 and Clark 20.
Real-time data is available for all of the wells and may be accessed on the U.S. Geological Survey website.
Acknowledgments
This report has been compiled from Division of Water data and from information supplied by the following:
Precipitation data:
National Oceanic and Atmospheric Administration, National Weather Service, Midwestern Regional Climate Center
Standardized Precipitation Index (SPI):
National Drought Mitigation Center (NDMC) and Western Regional Climate Center (WRCC)
Streamflow:
U.S. Geological Survey and State of Indiana cooperative program
Lake Michigan level data:
U.S. Army Corps of Engineers, Detroit District
Reservoir data:
U.S. Army Corps of Engineers, Louisville District
Groundwater level data:
U.S. Geological Survey and State of Indiana cooperative program
Temperature data:
Midwestern Regional Climate Center and Indiana State Climate Office, Purdue University
