National Weather Service Forecast for: Allentown PA
Issued by: National Weather Service Philadelphia, PA
Updated: 4:08 am EDT Aug 20, 2026
 
Today

Today: A chance of showers, then showers and thunderstorms after noon. High near 76. Calm wind becoming north around 5 mph in the afternoon. Chance of precipitation is 90%. New rainfall amounts between three quarters and one inch possible.
Chance
Showers then
T-storms
 Tonight

Tonight: Showers and thunderstorms likely, mainly before 8pm. Mostly cloudy, with a low around 61. Northeast wind around 5 mph becoming calm in the evening. Chance of precipitation is 60%. New precipitation amounts between a quarter and half of an inch possible.
T-storms
Likely then
Partly Cloudy
 Friday

Friday: Mostly sunny, with a high near 80. Calm wind becoming northeast around 5 mph.
Mostly Sunny

 Friday
Night
Friday Night: A slight chance of showers, then a chance of showers and thunderstorms after 2am. Increasing clouds, with a low around 64. Calm wind. Chance of precipitation is 50%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
Slight Chance
Showers then
Chance
Showers
 Saturday

Saturday: A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 8am. Mostly cloudy, with a high near 78. Calm wind becoming east around 5 mph. Chance of precipitation is 60%. New rainfall amounts between a quarter and half of an inch possible.
Showers
Likely

 Saturday
Night
Saturday Night: A chance of showers and thunderstorms before 8pm, then a chance of showers between 8pm and 2am. Mostly cloudy, with a low around 65. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
Chance
T-storms then
Chance
Showers
 Sunday

Sunday: A chance of showers after 2pm. Partly sunny, with a high near 82. Chance of precipitation is 40%.
Partly Sunny
then Chance
Showers
 Sunday
Night
Sunday Night: A chance of showers before 8pm. Partly cloudy, with a low around 61. Chance of precipitation is 30%.
Chance
Showers then
Mostly Clear
 Monday

Monday: Sunny, with a high near 78.
Sunny
Hi 76 °F Lo 61 °F Hi 80 °F Lo 64 °F Hi 78 °F Lo 65 °F Hi 82 °F Lo 61 °F Hi 78 °F

 

Today
 
 A chance of showers, then showers and thunderstorms after noon. High near 76. Calm wind becoming north around 5 mph in the afternoon. Chance of precipitation is 90%. New rainfall amounts between three quarters and one inch possible.
Tonight
 
 Showers and thunderstorms likely, mainly before 8pm. Mostly cloudy, with a low around 61. Northeast wind around 5 mph becoming calm in the evening. Chance of precipitation is 60%. New precipitation amounts between a quarter and half of an inch possible.
Friday
 
 Mostly sunny, with a high near 80. Calm wind becoming northeast around 5 mph.
Friday Night
 
 A slight chance of showers, then a chance of showers and thunderstorms after 2am. Increasing clouds, with a low around 64. Calm wind. Chance of precipitation is 50%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
Saturday
 
 A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 8am. Mostly cloudy, with a high near 78. Calm wind becoming east around 5 mph. Chance of precipitation is 60%. New rainfall amounts between a quarter and half of an inch possible.
Saturday Night
 
 A chance of showers and thunderstorms before 8pm, then a chance of showers between 8pm and 2am. Mostly cloudy, with a low around 65. Chance of precipitation is 40%. New precipitation amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
Sunday
 
 A chance of showers after 2pm. Partly sunny, with a high near 82. Chance of precipitation is 40%.
Sunday Night
 
 A chance of showers before 8pm. Partly cloudy, with a low around 61. Chance of precipitation is 30%.
Monday
 
 Sunny, with a high near 78.
Monday Night
 
 Mostly clear, with a low around 59.
Tuesday
 
 Sunny, with a high near 79.
Tuesday Night
 
 Mostly clear, with a low around 60.
Wednesday
 
 A chance of showers. Mostly sunny, with a high near 82. Chance of precipitation is 30%.

 

Forecast from NOAA-NWS for Allentown PA.