Sun, Storms, and Surprises: What Chester County’s Week Really Looks Like

Chester County Weather

CHESTER COUNTY, PA — As summer fades into fall, Chester County is in for a mixed bag of weather this week. Expect a pleasant start, some stormy interruptions midweek, and a stretch of cloudy, unsettled skies as we head into the weekend. Let’s take a closer look at what the skies have in store starting Sunday, September 21, 2025.


Sunday: Clouds Clearing Out

Today begins on the gray side but brightens as the hours tick by. Highs reach near 75°F once the sun pushes through, with a light southeast breeze at 5 mph. Tonight, skies stay mostly clear, and we’ll cool down to a comfortable 52°F — great sleeping weather.


Monday: Smooth Sailing

Monday brings plenty of sunshine with highs near 79°F. Winds remain calm, shifting south at 5 mph by afternoon. Monday night clouds roll back in, but lows stay mild around 60°F.

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Tuesday: Storm Chances Return

Tuesday is partly sunny with highs near 83°F, but things may get bumpy in the afternoon. There’s a 40% chance of showers and thunderstorms after 2 p.m., with more rain possible into the night (50% chance). Rainfall should be light overall, but storms could bring locally higher amounts. Overnight lows hold around 63°F.


Wednesday: Spotty Showers

Expect mostly cloudy skies with highs near 78°F. Showers may pop up in the afternoon (30% chance), continuing into the night with lows around 61°F.


Thursday Through Saturday: Cloudy and Damp

The back half of the week turns unsettled:

  • Thursday: Mostly cloudy with a 40% chance of showers, highs near 72°F, and lows around 60°F.
  • Friday: Same story — cloudy with a 40% chance of showers, highs near 74°F, lows around 62°F.
  • Saturday: Showers remain possible (40% chance), highs near 75°F.
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The Takeaway

This week in Chester County starts with sunshine and ends with a string of cloudy, damp days. The best weather comes early — Sunday and Monday — before storms and showers begin to dominate. Highs stay comfortable in the 70s to low 80s, while lows dip into the 50s and low 60s.


☀️ Want to stay one step ahead of the midweek storms? Visit the MyChesCo Weather Center for live forecasts, radar, and real-time updates tailored for Chester County.

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