This a question we on the weather team are asked a lot this time of year. Generally the rule of thumb is to wait until after Mother's Day to be safe, but we dug through the records to see if there's a better date we can give you that's more specific to our area. The data in the map below from the MRCC Vegetation Impact Program shows mid- to late April as a good estimation of when freezes become less likely.
First, a point of clarification. A hard freeze is a temperature of 28º (or colder), a freeze is reaching 32º (32-29), and a frost is reaching 36º (36-33). According to statistics for the city of Louisville compiled by the National Weather Service, the normal latest hard freeze is March 23; the normal latest freeze is April 3; and the normal latest frost is April 14th. The map below from the National Weather service looks even farther back in the records to show the average last freeze date around our communities.
The catch is we have seen frosts/freezes/hard freezes happen later than that. The record for latest frost is May 27 (1961), latest freeze is May 10 (1966), and latest hard freeze is April 23 (1986). Even by those numbers we are just about out of the danger zone. While we can't 100% guarantee Mother Nature won't do something strange, you should be safe at this point to get those plants in the ground. Happy planting!Â
