Morning Fog to Give Way to Record-Challenging Afternoon Warmth

A Day of Drastic Transitions

St. Louis residents are waking up to a thick blanket of gray this Friday morning, February 27, 2026. The National Weather Service has issued an early morning advisory regarding dense fog that has developed across portions of south-central Illinois and expanded westward into the St. Louis metropolitan area. Commuters are urged to exercise extreme caution during the early hours, as visibility is significantly reduced across major interstates and residential corridors.

Morning Forecast: Low Visibility and Chill

The morning starts with a damp chill, with temperatures sitting near 38°F and humidity levels reaching a near-saturation point of 95%. The primary concern through 9:00 AM remains the dense fog. If you are traveling early, be sure to use low-beam headlights and allow for extra following distance. This misty start, however, is merely the precursor to a remarkably pleasant day as the fog is expected to burn off by mid-morning, giving way to clear, blue skies.

Afternoon Forecast: Unseasonable Spring-Like Heat

By early afternoon, the St. Louis region will experience a dramatic shift in conditions. As the sun takes hold, temperatures are projected to climb rapidly, reaching a high of 71°F to 73°F. This is significantly higher than the typical late February averages and will challenge historic records for this date. With a 0% chance of rain and humidity dropping to a comfortable 49%, it is an ideal afternoon for outdoor activities at Forest Park or a walk along the Riverfront. Light breezes will keep the air moving, though no significant wind warnings are currently in effect.

Evening and Nighttime: Clear and Crisp

As the sun sets, the clear conditions will persist into the evening. The transition to night will bring a steady drop in temperature, eventually settling into a low of approximately 39°F. While the afternoon may feel like early May, the night will serve as a reminder that winter has not yet fully retreated. Skies will remain clear throughout the night, providing excellent visibility for stargazing without the threat of returning fog or precipitation.

Today’s Weather Highlights

• High Temperature: 71°F to 73°F (Unseasonably warm)
• Low Temperature: 38°F to 39°F
• Hazards: Dense fog advisory through mid-morning; use caution on the roads.
• Rain Chance: 0% throughout the day and evening.
• Conditions: Morning fog transitioning to a sunny afternoon and clear night.