Safe to plant? Why we've probably seen the last 32-degree temp at MSP this spring

Have we seen the last freeze of the spring season in the Twin Cities?

That’s a question I get a lot this time of year. Back in the day, the typical wisdom was it wasn’t safe to plant until around Memorial Day. But as Minnesota’s climate has warmed, our growing season has expanded and the date of the average last freeze of spring has shifted earlier.

As you can see on the graphic above, the average date of the last 32 at the Minneapolis-St. Paul International Airport is April 25. That means half the time the last freeze occurs later than April 25. The last time we recorded 32 or colder at MSP Airport this spring was April 21 at 29 degrees. We came close on April 25 with 33 degrees.

Frost and freezing temperature are still likely in central and northern Minnesota through May and can even occur into June in northeast Minnesota. It’s almost certainly too early to plant those tender annuals north of the Twin Cities.

Twin Cities: A few more 30s ahead?

Friday morning brings a freeze to most of central and northern Minnesota. The Twin Cities and southern Minnesota will bottom out in the lower 40s.

The forecast models suggest we may see a couple more nights in the mid or upper 30s next week in the Twin Cities. But medium-range temperature guidance keeps the Twin Cities above freezing for the next 16 days.

I’d estimate a 70 to 80 percent chance we’ll stay above 32 degrees at MSP Airport for the next two weeks. That puts us into mid-May when the chance for a freeze in the Twin Cities rapidly declines.

Soil temperature in the low 50s

Soil temperature at several locations in Minnesota have warmed into the upper 40s and 50s. Here’s the chart from southwest Minnesota near Marshall.

Here at the Weather Lab we are going ahead with spring planting. We’re fine with covering up anything if needed on the occasional chilly night for the next couple of weeks.

Happy spring!