National Oceanic and Atmospheric Administration National Weather Service United States Department of Commerce

Dangerous Heat and Heavy Rainfall into the Weekend

Hot temperatures and high humidity are forecast to continue across the mid-Mississippi Valley into this weekend. Heat Advisories remain in effect. Heavy to excessive rainfall occurring at times through the weekend could bring areas of flooding to parts of the northern Rockies, upper Midwest, central Great Lakes, and southern New England. Read More >

Current conditions at

Pottstown, Pottstown Limerick Airport (KPTW)

Lat: 40.24°NLon: 75.55°WElev: 288ft.

Fair

65°F

18°C

Humidity 68%
Wind Speed Calm
Barometer 30.16 in (1020.8 mb)
Dewpoint 54°F (12°C)
Visibility 10.00 mi
Last update 19 Sep 12:54 am EDT
Extended Forecast for

Collegeville PA

  • Overnight

    Overnight: Partly cloudy, with a low around 55. North wind around 5 mph.

    Low: 55 °F

    Partly Cloudy

  • Saturday

    Saturday: Mostly sunny, with a high near 74. East wind 5 to 10 mph.

    High: 74 °F

    Mostly Sunny

  • Saturday Night

    Saturday Night: A chance of showers, mainly after 5am. Patchy fog after 10pm. Otherwise, increasing clouds, with a low around 61. Southeast wind around 5 mph. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

    Low: 61 °F

    Patchy Fog
    then Chance
    Showers and
    Patchy Fog

  • Sunday

    Sunday: Showers likely, then showers and possibly a thunderstorm after 2pm. Some of the storms could produce heavy rainfall. High near 75. Southeast wind around 10 mph. Chance of precipitation is 80%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.

    High: 75 °F

    Heavy Rain

  • Sunday Night

    Sunday Night: Showers and possibly a thunderstorm before 2am, then a chance of showers. Some of the storms could produce heavy rainfall. Patchy fog. Low around 60. Southwest wind around 5 mph becoming north after midnight. Chance of precipitation is 80%. New rainfall amounts between a quarter and half of an inch possible.

    Low: 60 °F

    Heavy Rain
    and Patchy
    Fog

  • Monday

    Monday: A chance of showers. Mostly cloudy, with a high near 69. Chance of precipitation is 40%. New precipitation amounts between a tenth and quarter of an inch possible.

    High: 69 °F

    Chance
    Showers

  • Monday Night

    Monday Night: A chance of showers. Mostly cloudy, with a low around 54. Chance of precipitation is 30%.

    Low: 54 °F

    Chance
    Showers

  • Tuesday

    Tuesday: A chance of showers. Mostly cloudy, with a high near 64. Chance of precipitation is 40%.

    High: 64 °F

    Chance
    Showers

  • Tuesday Night

    Tuesday Night: A chance of showers. Mostly cloudy, with a low around 51. Chance of precipitation is 30%.

    Low: 51 °F

    Chance
    Showers

Detailed Forecast

Overnight
Partly cloudy, with a low around 55. North wind around 5 mph.
Saturday
Mostly sunny, with a high near 74. East wind 5 to 10 mph.
Saturday Night
A chance of showers, mainly after 5am. Patchy fog after 10pm. Otherwise, increasing clouds, with a low around 61. Southeast wind around 5 mph. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.
Sunday
Showers likely, then showers and possibly a thunderstorm after 2pm. Some of the storms could produce heavy rainfall. High near 75. Southeast wind around 10 mph. Chance of precipitation is 80%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.
Sunday Night
Showers and possibly a thunderstorm before 2am, then a chance of showers. Some of the storms could produce heavy rainfall. Patchy fog. Low around 60. Southwest wind around 5 mph becoming north after midnight. Chance of precipitation is 80%. New rainfall amounts between a quarter and half of an inch possible.
Monday
A chance of showers. Mostly cloudy, with a high near 69. Chance of precipitation is 40%. New precipitation amounts between a tenth and quarter of an inch possible.
Monday Night
A chance of showers. Mostly cloudy, with a low around 54. Chance of precipitation is 30%.
Tuesday
A chance of showers. Mostly cloudy, with a high near 64. Chance of precipitation is 40%.
Tuesday Night
A chance of showers. Mostly cloudy, with a low around 51. Chance of precipitation is 30%.
Wednesday
A chance of showers. Mostly cloudy, with a high near 62. Chance of precipitation is 40%.
Wednesday Night
A chance of showers. Mostly cloudy, with a low around 51. Chance of precipitation is 40%.
Thursday
A chance of showers. Mostly cloudy, with a high near 63. Chance of precipitation is 30%.
Thursday Night
A chance of showers. Mostly cloudy, with a low around 51. Chance of precipitation is 30%.
Friday
Partly sunny, with a high near 68.
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ABOUT THIS FORECAST

 
Point Forecast:
Collegeville PA
 40.19°N 75.46°W (Elev. 200 ft)
Last Update:
4:10 pm EDT Sep 18, 2026
Forecast Valid:
12am EDT Sep 19, 2026-6pm EDT Sep 25, 2026
 
Forecast Discussion
 
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Additional Resources

Radar & Satellite Image

Link to Local Radar Data Link to Satellite Data

Hourly Weather Forecast

National Digital Forecast Database

National Digital Forecast Database Maximum Temperature Forecast

High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation