St. Louis, MO – The Mississippi River valley starts this week in a deep chill, with temperatures in the mid-20s and gray skies blanketing the metro. But the calm won’t last long — a brief December warm-up will push highs back into the 50s by Tuesday, before another cold front and light snow make a return late week.
According to the National Weather Service in St. Louis, clouds will thin Monday as drier air moves in, allowing for gradual clearing and a high near 34°F. Winds remain light, but by Tuesday, a southern flow builds warmth across the region, sending afternoon highs into the low 50s — nearly 20 degrees above today’s chill.
By Wednesday, expect another mild day near 47°F, followed by a colder push from the northwest late Wednesday night. Thursday brings a 20% chance of snow, mainly north and west of the metro, though flakes may drift toward I-70 and downtown St. Louis by evening. Temperatures will fall through the 30s, and patchy black ice could form on untreated bridges or side streets as moisture freezes.
The weekend stays cold and mostly clear, with highs in the upper 20s to low 30s. Friday and Saturday mornings could dip into the teens, marking another early-winter cold snap.
Meteorologists say this back-and-forth pattern signals a classic December transition, where Arctic air from the Midwest clashes with milder southern flow — a setup that often leads to quick shifts and surprise flurries.
