We're starting to get back into that time of year again. Temperatures are starting to warm more as we are now officially in Spring, but next thing you know it can get really cold a day later and if you've planted anything, you know that could mean big trouble. 

Most local folks around here know that the general rule is no planting before Derby. That does have some truth to it, but let's go through why that is and dive into some records from Louisville about how this relates to past events here.

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 20th; the normal latest freeze is March 31st; and the normal latest frost is April 11th. 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. Note how cities outside of Louisville (even in Jefferson County) have drastically different dates and statistics. 

The data in the map below from the MRCC Vegetation Impact Program shows late March for the Louisville area and mid-late April for the rest of the area as a good estimation of when freezes become less likely. As of today, we are within about a weeks range across most of Kentuckiana.

The catch is we have seen frosts/freezes/hard freezes happen later than that Kentuckiana. Therefore, we can't 100% guarantee Mother Nature will not do something strange. Check out the records for the latest frost, freeze and hard freeze below. While we are not quite to the safe zone yet - we will be there in the week or so for most of us! Plus, if you really want to plant now, you can carefully watch the forecast, and take precautions to protect your vegetation if needed!

RECORDS: *Please note that these statistics are for Louisville*

-Latest spring frost (36°):  May 27, 1961

-Latest spring freeze (32°):  May 10, 1966

-Latest spring hard freeze (28°):  April 23, 1986

-Earliest final spring frost (36°):  March 15, 1884

-Earliest final spring freeze (32°):  March 5, 1927