It’s … hot in Metro Detroit right now.

That’s a weird thing to say in April, but it’s true: High temperatures have been in the 70s and 80s, and they’ll stay that way this week.

With all this warmth, you may be switching to springtime gardening mode. But, is it safe to start planting outdoors in Southeast Michigan? Are we done with the cold temperatures for the season?

Our warm temperature outlook is promising (if you like the heat, that is), but it’s still fairly soon to start planting. Here’s what to know.

It’s all about soil temperature

When deciding when to plant outdoors in the spring, it’s important to consider the soil temperature in addition to the air temperature. Just because it’s warm outside doesn’t necessarily mean the soil is warm enough to plant.

The ideal soil temperature for planting most plants, especially vegetables, is between 65-75 degrees.

Planting in soil that is colder than 50 degrees could lead to germination problems with the plants, even if the air temperature is above freezing.

You can take the temperature of your soil yourself to see if the conditions are right.

When is the best time to plant in Southeast Michigan?

The time when it becomes safe to plant varies each year, since temperature trends aren’t exactly the same year-to-year.

With that in mind, our 4Warn Meteorologist Ashlee Baracy maintains that it’s safest to plant in the spring in mid- to late May.

Sure, our temps will reach the 70s and 80s during the day this week, but that may not last. And overnight low temperatures will drop into the 50s, and even the 40s at times.

In 2023, mid-April soil temperatures rose to around 70 degrees due to a stretch of days with 80-degree air temperatures. By the end of the month, though, soil temperatures were hovering in the 40s.

It’s best to plant when there’s at least some certainty that the high temperatures won’t suddenly drop below 50 or 40 degrees. It’s also ideal to avoid planting if frost remains a concern.

Are we done with frost this spring?

We may not have to worry about frost anymore this spring, but it’s still a possibility.

Frost is a thin layer of ice that forms on surfaces, and can “threaten sensitive vegetation and agriculture,” the National Weather Service says. Frost forms when air temperatures are at or below the freezing mark: 32 degrees.

According to Meteorologist Ashlee Baracy, our average “last freeze” of the spring season is on April 24.

The last day of frost in the spring of 2023 was April 26. The latest freeze that Metro Detroit has ever seen was on May 29, 1966.

That’s why our 4Warn Weather team insists that sensitive plants should wait to get planted until around Memorial Day.

Temperatures in Southeast Michigan have been trending above average this season, though. Across Michigan, temperatures are expected to remain above average in May. See the long range forecast for May here.

As of Monday, April 29, the lowest temperature in our 10-day forecast will be a 48-degree low on Tuesday, April 30.

See the 10-day forecast here.