National Weather Service Forecast for: Olney MD
Issued by: National Weather Service Baltimore, MD/Washington, D.C.
Updated: 2:22 am EDT Aug 20, 2026
 
Overnight

Overnight: Isolated showers, with thunderstorms also possible after 5am. Mostly cloudy, with a low around 69. Calm wind. Chance of precipitation is 20%.
Isolated
T-storms

 Thursday

Thursday: Scattered showers and thunderstorms, then showers and possibly a thunderstorm after 2pm. High near 82. Calm wind becoming west around 6 mph in the afternoon. Chance of precipitation is 90%. New rainfall amounts between a quarter and half of an inch possible.
Isolated
T-storms then
Showers

 Thursday
Night
Thursday Night: Showers and thunderstorms likely, mainly before 9pm. Patchy fog between 9pm and 2am. Otherwise, mostly cloudy, with a low around 64. North wind 3 to 5 mph. Chance of precipitation is 60%. New precipitation amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.
Showers
Likely and
Patchy Fog
then Patchy
Fog
 Friday

Friday: Mostly sunny, with a high near 78. North wind around 5 mph becoming light and variable in the afternoon.
Mostly Sunny


 Friday
Night
Friday Night: A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 2am. Mostly cloudy, with a low around 66. Calm wind. Chance of precipitation is 70%.
Showers
Likely

 Saturday

Saturday: Showers likely and possibly a thunderstorm before 11am, then a chance of showers and thunderstorms between 11am and 2pm, then showers likely and possibly a thunderstorm after 2pm. Mostly cloudy, with a high near 80. Chance of precipitation is 60%.
Showers
Likely

 Saturday
Night
Saturday Night: Showers and thunderstorms likely before 11pm, then a chance of showers between 11pm and 2am. Mostly cloudy, with a low around 66. Chance of precipitation is 60%.
Showers
Likely

 Sunday

Sunday: A chance of showers and thunderstorms after 2pm. Mostly sunny, with a high near 81. Chance of precipitation is 30%.
Mostly Sunny
then Chance
Showers

 Sunday
Night
Sunday Night: A chance of showers and thunderstorms before 8pm. Mostly clear, with a low around 62. Chance of precipitation is 30%.
Chance
Showers then
Mostly Clear
Lo 69 °F Hi 82 °F Lo 64 °F Hi 78 °F Lo 66 °F Hi 80 °F Lo 66 °F Hi 81 °F Lo 62 °F

Hazardous Weather Outlook
 

Overnight
 
 Isolated showers, with thunderstorms also possible after 5am. Mostly cloudy, with a low around 69. Calm wind. Chance of precipitation is 20%.
Thursday
 
 Scattered showers and thunderstorms, then showers and possibly a thunderstorm after 2pm. High near 82. Calm wind becoming west around 6 mph in the afternoon. Chance of precipitation is 90%. New rainfall amounts between a quarter and half of an inch possible.
Thursday Night
 
 Showers and thunderstorms likely, mainly before 9pm. Patchy fog between 9pm and 2am. Otherwise, mostly cloudy, with a low around 64. North wind 3 to 5 mph. Chance of precipitation is 60%. New precipitation amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.
Friday
 
 Mostly sunny, with a high near 78. North wind around 5 mph becoming light and variable in the afternoon.
Friday Night
 
 A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 2am. Mostly cloudy, with a low around 66. Calm wind. Chance of precipitation is 70%.
Saturday
 
 Showers likely and possibly a thunderstorm before 11am, then a chance of showers and thunderstorms between 11am and 2pm, then showers likely and possibly a thunderstorm after 2pm. Mostly cloudy, with a high near 80. Chance of precipitation is 60%.
Saturday Night
 
 Showers and thunderstorms likely before 11pm, then a chance of showers between 11pm and 2am. Mostly cloudy, with a low around 66. Chance of precipitation is 60%.
Sunday
 
 A chance of showers and thunderstorms after 2pm. Mostly sunny, with a high near 81. Chance of precipitation is 30%.
Sunday Night
 
 A chance of showers and thunderstorms before 8pm. Mostly clear, with a low around 62. Chance of precipitation is 30%.
Monday
 
 Sunny, with a high near 78.
Monday Night
 
 Mostly clear, with a low around 61.
Tuesday
 
 Mostly sunny, with a high near 79.
Tuesday Night
 
 Partly cloudy, with a low around 64.
Wednesday
 
 A chance of showers and thunderstorms. Mostly sunny, with a high near 82. Chance of precipitation is 30%.

 

Forecast from NOAA-NWS for Olney MD.