Climatology

The Rathbun Lake area has a variable climate of moderate winters and comparatively long summers. The humid climate characteristic of the mid-continent region has wide variations in temperature and rainfall, occasional high winds and cyclonic disturbances. Average annual precipitation varies from 32 to 38 inches from the north to south, in the Chariton River Basin. The long term mean precipitation at Centerville, Iowa is about 33 inches. About 70% of the annual precipitation occurs during the 180 day growing season, April through September. Snowfall generally occurs from November through March and averages 25.2 inches per year. The mean Monthly temperature is 51 degrees Fahrenheit. Recorded temperatures have ranged from –25 degrees to +104 degrees. Winds are predominately from the south during the summer and north to northwest in the winter. March, April and May are the months of highest sustained wind readings. Evaporation from the reservoir surface averages 37 inches per year.

Drought Monitor