ASK ELi: Chance of Frost?

Above: The author now has seedlings under glass and also exposed in his East Lansing backyard

A gardening reader asks: What is the chance of a frost yet this spring in East Lansing?

The answer: For any given year, there is not a certain date after which a gardener knows there will not be a frost. But based on prior years, it is possible to know how likely a frost is after a particular date. Based on information from the National Climatic Data Center, East Lansing has a 50% chance of having a frost after May 4^th. (For ELi’s purposes, we are using a low daily temperature of 32 F as the definition of a frost.)

For many plants that can handle a little cold, the 50% frost date is a pretty safe date to plant perennials and other plants that can take a joke. If you are planting a truly tender plant or a plant you don’t want to risk, then waiting a few weeks until after May 20^th is a better idea because there is only a 10% chance of a frost after May 20^th.

The author has already put out some tender plants under the protection of plastic or glass, which helps protect tender plants from cold temperatures. In the spirit of full disclosure, the author has kept some of the same types of seedlings safely in his basement under grow lights in case there is a bad frost in the next month or so.

The Lansing frost dates in the table below are a little different than the East Lansing dates from the same table. The National Climatic Data comes from weather stations in the area and each station has recorded slightly different information over the years. Some of this may be due to the geography and city-scape around the station. The East Lansing station is near the intersection of Michigan Route 127 and Interstate 96, while the Lansing data comes from the weather station at the Capital City Airport in Lansing.

Data from National Climatic Data Center at NOAA