Although meteorological summer officially began on June 1st, much of the area is still waiting for their first 90-degree days. Columbia and St. Louis are both behind schedule on reaching this mark, thanks to a wetter and milder start to the season.

On average, Columbia sees its first 90-degree day on the very last day of May, on the 31st. The latest 90-degree day on record for Columbia is July 14, 1904. Temperature records for Como go back to the 1890s.

For St. Louis, the average first 90-degree day is even earlier on May 20th, and the latest 90-degree day on record is also earlier, on July 4th in both 1961 and 1912. Records in St. Louis stretch back to 1874.

As STL has yet to reach 90 degrees this year, this puts 2025 in the top 20 all-time latest dates for the first 90-degree day - the latest in at least 30 years (June 19, 1995).

These temperature records are not influenced by urban heat island effects, as Columbia's official records are taken from the Columbia Regional Airport near Ashland. St. Louis temperature records are taken at Lambert International Airport, which also eliminates the influence of urban heat.

Current forecasts suggest the first 90-degree day for Columbia and St. Louis may occur by June 17th, this upcoming Tuesday. However, there is a decent spread in temperature forecasts across our weather models, and the 90-degree mark is in the upper end of the forecast. An ongoing active pattern of near-daily rain chances may stave off 90 degrees for even longer.