Decorah is still waiting for its first frost of the season. Temperatures are forecast to drop into the upper 30s on Sunday night, but a warming trend will begin Monday. As a result, the first frost of the season might not come until a few days before Halloween.
Decorah meteorologist Richard Bernatz says the median date for a first frost in Decorah is September 29th. That mean's half of all first frosts have come before September 29th and half have come after.
The earliest date of a first frost was August 30th in 1915. The latest date for a first frost was October 30th in 1973. Last year the first frost in Decorah came on October 8th.
Bernatz says the figures show there's no chance of frost before August 30th, a 50 percent chance of frost by September 29th and a 100 percent chance of frost by October 30th. But as Bernatz cautions, "Of course, rules are made to be broken."