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Posted: April 21, 2004
Updated April 30, 2009
HORTICULTURE Probability of a Frost/Freeze in the Spring for some Southwest Michigan Sites
Mark Longstroth District Horticultural Agent
Frosts in the Spring are a hazard to growers and gardeners anxious to start a new growing season. Freezing temperatures will kill actively growing fruit buds. As the buds develop they become less and less resistant to cold. At bloom fruit crops like apples suffer damage just below freezing. I have posted a table of critical temperatures for the fruit crops grown in SW Michigan. That table can be used with the table below for a measure of how much risk exists at any one time.
Frosts, with the formation of ice can happen without freezing tempertaures. Freezing temperatures will kill cold sensitive plants like tomatoes and corn and planting should be delayed until the danger of freezing temperature is past.
I have an old MSU publication from 1965, that lists the probability of a frost for some of the older US Weather Service recording weather stations in our region. I have extracted a partial table showing the probability of freezing temperatures for some SW Michigan sites. This table has three threshold temperatures;
The table below is arranged from North to South. Sites located away from Lake Michigan show the approximate distance to the lake. Sites near Lake Michigan show no distance. In the table 10% means there is a 10% chance of a freeze occurring on or after that date in the Spring.
| Percent probability of indicated temperature or lower occurring on or before date in Fall. | |||||
| Temperature | 90% | 75% | 50% | 25% | 10% |
| Holland - lakeshore | |||||
| 32 | April 24 | May 1 | May 9 | May 17 | May 24 |
| 30 | April 17 | April 24 | May 2 | May 10 | May 17 |
| 28 | April 12 | April 19 | April 27 | May 5 | May 12 |
| Allegan - 20 miles inland | |||||
| 32 | April 23 | April 30 | May 8 | May 16 | May 23 |
| 30 | April 17 | April 24 | May 2 | May 10 | May 17 |
| 28 | April 7 | April 14 | April 22 | April 30 | May 7 |
| South Haven - lakeshore | |||||
| 32 | April 20 | April 27 | May 5 | May 13 | May 20 |
| 30 | April 12 | April 19 | April 27 | May 5 | May 13 |
| 28 | April 6 | April 13 | April 21 | April 29 | May 5 |
| Percent probability of indicated temperature or lower occurring on or before date in Fall. | |||||
| Temperature | 90% | 75% | 50% | 25% | 10% |
| Bloomingdale - 15 miles inland | |||||
| 32 | April 26 | May 3 | May 11 | May 19 | May 26 |
| 30 | April 19 | April 26 | May 4 | May 12 | May 19 |
| 28 | April 11 | April 18 | April 26 | May 4 | May 11 |
| Paw Paw - 23 miles inland | |||||
| 32 | April 25 | May 2 | May 10 | May 18 | May 25 |
| 30 | April 22 | April 29 | May 7 | May 15 | May 22 |
| 28 | April 16 | April 23 | May 1 | May 9 | May 16 |
| Kalamazoo - 49 miles inland | |||||
| 32 | April 24 | May 1 | May 9 | May 17 | May 24 |
| 30 | April 18 | April 25 | May 3 | May 11 | May 18 |
| 28 | April 9 | April 16 | April 24 | May 2 | May 9 |
| St. Joseph - lakeshore | |||||
| 32 | April 10 | April 17 | April 25 | May 3 | May 10 |
| 30 | April 4 | April 11 | April 19 | April 27 | May 4 |
| 28 | March 25 | April 1 | April 9 | April 17 | April 24 |
| Percent probability of indicated temperature or lower occurring on or before date in Fall. | |||||
| Temperature | 90% | 75% | 50% | 25% | 10% |
| Eau Claire - 12 miles inland | |||||
| 32 | April 19 | April 26 | May 4 | May 12 | May 19 |
| 30 | April 12 | April 19 | April 27 | May 5 | May 12 |
| 28 | April 5 | April 12 | April 20 | April 28 | May 5 |
For more Michigan climate information including frost dates and other growing season information, check out the Michigan State Climatology Site. Click on the Michigan Map Link and choose the region you are interested in.
For more information on Frost and cold injury to plants check out my Frost Freeze Page.
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Posted: April 21, 2004
Updated April 30, 2009