The prevailing winds in the area are from the south. Although Southwest Indiana is 550 miles from the Gulf of Mexico, its weather is influenced by the warm moist air masses from the south. This pattern prevails most of the year although it is occasionally interrupted by cold fronts that slide south during the winter. Despite these cold periods, the weather overall is more southern than northern. This is frequently seen in the temperature variations between Spencer County and Chicago where it is not unusual to have more than a ten-degree difference in the winter. Snowfall varies a great deal from year to year and significant accumulation (6 inches or more) is rare.
Zero degree days - 3
Freezing days - 103
90 degree days - 39
Sunshine days - 203
Wind speed - 8.3 mph
Relative humidity - 70%
Average annual rainfall- 42 inches
Average annual snowfall - 13 inches