Columbus (WCMH) – I have been asked the question a lot lately, when is it safe or a good time to plant. Well it depends on a lot of things, most importantly if you trust me for your planting advice.
First off, I should note, I am in no way a green thumb!! I keep a nice lawn, and my shrubs look fine, but this story is more for freeze/frost data.May is going to start on quite a chilly note:
What I did is compared the 2nd through the 8th of March (Yellow) vs the 2nd-8th of April (Pink) vs. the FORECAST for the 2nd-8th of May (Green)
Notice that March did start the coldest with highs in the 40s and 30s, but actually by the 5th of the month might be a degree warmer than the 5th of May. March also kept track with May forecast temps after that point in the lower 60s.
April started almost the same, but actually will have a warmer period from the 2nd-8th than will the month of March.
While this chart isn’t a planning guide it is interesting that May is still starting this cool. It is also a good reminder.When is the latest you can expect freezing temperatures in May?
As 2016, just last year serves as a reminder, we can have freezing temperatures as late as the 16th day of May.
However, less than 1% (0.7%) of all days in the Month of May have experienced freezing or subfreezing temperatures.
30 of the 4,248 days in the month have achieved this, with the coldest temp coming on May 10, 1966 with a low of 25°
Below is a list of all the dates in May with a freeze:
| date | year | Low | |
| 1 | 1-May | 1978 | 30° |
| 2 | 1-May | 1963 | 30° |
| 3 | 1-May | 1971 | 31° |
| 4 | 1-May | 1943 | 31° |
| 5 | 2-May | 1994 | 30° |
| 6 | 2-May | 1963 | 30° |
| 7 | 2-May | 1978 | 31° |
| 8 | 2-May | 1961 | 32° |
| 9 | 3-May | 1978 | 30° |
| 10 | 4-May | 2005 | 31° |
| 11 | 4-May | 1986 | 31° |
| 12 | 4-May | 1966 | 31° |
| 13 | 5-May | 1979 | 32° |
| 14 | 6-May | 1968 | 29° |
| 15 | 6-May | 1957 | 32° |
| 16 | 7-May | 1974 | 31° |
| 17 | 7-May | 1989 | 32° |
| 18 | 7-May | 1970 | 32° |
| 19 | 8-May | 1954 | 31° |
| 20 | 8-May | 1947 | 32° |
| 21 | 9-May | 1983 | 30° |
| 22 | 9-May | 1966 | 30° |
| 23 | 9-May | 1947 | 30° |
| 24 | 9-May | 1923 | 31° |
| 25 | 9-May | 1980 | 32° |
| 26 | 10-May | 1966 | 25° |
| 27 | 10-May | 1983 | 32° |
| 28 | 10-May | 1977 | 32° |
| 29 | 16-May | 2016 | 32° |
| 30 | 16-May | 1959 | 32° |
It has also snowed about 2 dozen times in the month of May (since record keeping in 1879), however only one time it was measureable:
In May 9th, 1923 we recorded 0.3″ of snowfall, the heaviest in May history.
| date | year | Low | |
| 1 | 1-May | 1909 | Trace |
| 2 | 2-May | 1940 | Trace |
| 3 | 2-May | 1930 | Trace |
| 4 | 2-May | 1911 | Trace |
| 5 | 2-May | 1909 | Trace |
| 6 | 2-May | 1897 | Trace |
| 7 | 3-May | 1930 | Trace |
| 8 | 3-May | 1929 | Trace |
| 9 | 4-May | 1957 | Trace |
| 10 | 7-May | 1989 | Trace |
| 11 | 8-May | 1947 | Trace |
| 12 | 8-May | 1923 | Trace |
| 13 | 9-May | 1923 | 0.3″ |
| 14 | 9-May | 1966 | Trace |
| 15 | 9-May | 1954 | Trace |
| 16 | 9-May | 1930 | Trace |
| 17 | 9-May | 1906 | Trace |
| 18 | 11-May | 1966 | Trace |
| 19 | 14-May | 1895 | Trace |
| 20 | 14-May | 1888 | Trace |
| 21 | 15-May | 1904 | Trace |
Bottom line, to be very safe wait until the 2nd half of the month of May.
We have had a freeze as late as the 16th, and a dusting of snow as late as the 15th. While it is very unlikely, there is still about a 1% chance that we can see a freeze, frost, or very light snow during the first half of the month of May.The Climate Prediction Center’s 6-10, and 8-14 day forecasts also paint a cool picture for us:
Remember though, normal temperatures in this period range from 48° to 52°, so just because we are forecast to have “below normal” temperature trend, does not mean a freeze.
I am just your happy Meteorologist, not a gardener. You could probably be safe planting now, and just keep an eye on the forecast and protect the sensitive plants if the forecast requires.
If you ever have questions about frost, freeze, cold temps or anything else, email me: dmazza@wcmh.com
-Dave