Des Moines, Iowa — Temperatures are expected to fall below 32° overnight across all of Iowa, so a Freeze Warning has been issued for central and southern Iowa from 1-8 AM Tuesday.

A Freeze Warning is only issued during the growing season. Sensitive plants and vegetation should be covered or brought inside to protect from the cold. Freezing temperatures can kill sensitive, unprotected plants.

Even though temperatures will fall into the 20s across northern Iowa, a freeze warning is not in effect in this area. The National Weather Service in Des Moines said this is because “the north has yet to see the repetitive number of days with very warm temperatures as the south has this past month.”

Today

This surge of cold air is due to a cold front that passed through the state last night. Clouds have moved in and will hang around the state today which will keep highs in the upper 40s. It will, however, feel a bit cooler thanks to a 10-20 mph northwest wind.

Tonight

As low pressure departs east and high pressure arrives from the west, cloud cover will clear and the wind will weaken by the evening. This will set Iowa up to dip back into the 20s and 30s early Tuesday morning.

Tuesday afternoon

Sunshine and lighter wind will hang around through Tuesday thanks to high pressure. This will help temperatures return to the upper 50s despite a cold start to the day.

What is the average last freeze in Iowa?

Iowa is behind schedule for its last freeze of the spring season.
Between 1981 and 2010 the average last freeze was:

  • Lamoni: April 5
  • Des Moines: April 7
  • Newton: April 8
  • Ames: April 9
  • Ottumwa: April 9
  • Indianola: April 13
  • Creston: April 14
  • New Hampton: April 14
  • Perry: April 14
  • Iowa Falls: April 14
  • Marshalltown: April 15
  • Fort Dodge: April 15
  • Algona: April 16
  • Carroll: April 16
  • Guthrie Center: April 20
  • Chariton: April 22

Last freeze in May?

In Des Moines, out of 143 years, there have been 16 years (11% of years with data) when the final freeze was recorded in May. The most recent year that occurred was 2005 when a low of 30° was recorded on May 3rd.

In the past 10 years, Des Moines has seen its last freeze between April 4 and April 28. If Tuesday’s morning low drops below 32° but is the last sub-32° temperature of the season, it will make 2022’s final spring freeze the 2nd latest.

What’s the temperature trend over the next couple weeks?

Tonight looks to be the only night with sub-freezing temperatures, as warmer air returns Tuesday night into Wednesday morning. Lows temperatures between Wednesday morning and Sunday morning will range between the upper 30s to the lower 50s.

The Climate Prediction Center’s 8-14 day temperature outlook for May 2-8 shows near average temperatures. Average low temperatures for this period range from 47-49°.