CHESTER COUNTY, PA — If you thought fall had fully arrived, think again. Chester County is getting one more round of summer-like warmth before cool, crisp air moves back in midweek. Expect sunny skies, some foggy mornings, and a dramatic drop in temperatures once midweek showers sweep through. Here’s your full outlook for the week starting Sunday, October 5, 2025.
Sunday: Sunny and Surprisingly Warm
Today expect a bright, sunny day with highs around 81°F. Winds will stay light, shifting south at about 5 mph. Tonight brings mostly clear skies and a low near 51°F, with fog likely to redevelop after 11 p.m.
Monday: Another Day of Sunshine
Monday keeps the streak going with more sunshine and a high near 79°F. Winds remain calm, becoming a gentle southwest breeze in the afternoon. Overnight, skies stay mostly clear with a low around 57°F, and you guessed it — more fog possible after midnight.
Tuesday: Breezy and Bright, Then Stormy
Tuesday starts mild and mostly sunny with a high near 79°F, but winds will pick up from the south at 5 to 10 mph, gusting up to 20 mph. That’s the sign of change. After midnight, expect showers and possibly a thunderstorm, with an 80% chance of rain. Rainfall could reach a half-inch in spots. Overnight lows dip to about 58°F.
Wednesday: Cooler and Clearing Out
Showers linger early Wednesday morning but taper off quickly. The rest of the day will turn partly sunny, though noticeably cooler, with highs near 69°F. By night, skies clear and temperatures drop to 45°F — a perfect evening for hot cocoa and flannel.
Thursday and Friday: Fall in Full Force
Thursday brings that classic autumn feel — sunshine, a crisp breeze, and a high around 63°F. Overnight, temperatures fall to 43°F under mostly clear skies.
Friday stays pleasant with highs near 65°F, mostly sunny skies, and cool evening lows around 47°F.
Saturday: A Perfect October Weekend
Saturday wraps up the week on a beautiful note — sunshine and a high near 70°F. Expect mild winds and dry skies, perfect for farmers’ markets, football, or leaf-peeping adventures.
The Takeaway
Chester County’s weather this week is a tale of two seasons: early-week warmth with a touch of summer, followed by a sharp cooldown that will remind everyone fall is officially here. Highs start in the 80s and end in the 60s, while lows dip into the 40s by midweek.
So, enjoy the sunshine while it lasts — just don’t put away that jacket yet.
☀️ Stay ahead of shifting skies and chilly nights — visit the MyChesCo Weather Center for real-time updates, local radar, and forecasts that keep you ready for whatever Mother Nature brings.
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