National Weather Service Forecast for: Ontario International Arpt CA
Issued by: National Weather Service San Diego, CA
Updated: 12:35 pm PST Dec 22, 2025
 
Tonight

Tonight: Patchy fog after 4am. Otherwise, mostly cloudy, with a low around 52. West wind around 5 mph becoming calm in the evening.
Mostly Cloudy
then Patchy
Fog

 Tuesday

Tuesday: Showers likely, mainly after 4pm. Patchy fog before 10am. Otherwise, mostly cloudy, with a high near 66. Northeast wind around 5 mph becoming calm in the afternoon. Chance of precipitation is 60%.
Slight Chance
Showers and
Patchy Fog
then Showers
Likely
 Tuesday
Night
Tuesday Night: Showers. The rain could be heavy at times. Low around 57. East wind 5 to 10 mph, with gusts as high as 20 mph. Chance of precipitation is 90%. New precipitation amounts between 1 and 2 inches possible.
Heavy Rain


 Wednesday

Wednesday: Showers, with thunderstorms also possible after 10am. Some of the storms could produce heavy rainfall. High near 63. Light and variable wind becoming south 5 to 10 mph in the morning. Winds could gust as high as 20 mph. Chance of precipitation is 100%. New rainfall amounts between 2 and 3 inches possible.
Heavy Rain


 Wednesday
Night
Wednesday Night: Showers and possibly a thunderstorm. Some of the storms could produce heavy rainfall. Low around 54. Southwest wind 5 to 10 mph becoming light and variable. Chance of precipitation is 100%. New rainfall amounts between a quarter and half of an inch possible.
Heavy Rain


 Christmas
Day
Christmas Day: Showers. High near 62. Chance of precipitation is 80%.
Showers


 Thursday
Night
Thursday Night: Showers. Low around 51. Chance of precipitation is 90%.
Showers


 Friday

Friday: Showers. Mostly cloudy, with a high near 60.
Showers


 Friday
Night
Friday Night: Showers likely, mainly before 10pm. Mostly cloudy, with a low around 44.
Showers
Likely
Lo 52 °F Hi 66 °F Lo 57 °F Hi 63 °F Lo 54 °F Hi 62 °F Lo 51 °F Hi 60 °F Lo 44 °F

Flood Watch
Wind Advisory
 

Tonight
 
 Patchy fog after 4am. Otherwise, mostly cloudy, with a low around 52. West wind around 5 mph becoming calm in the evening.
Tuesday
 
 Showers likely, mainly after 4pm. Patchy fog before 10am. Otherwise, mostly cloudy, with a high near 66. Northeast wind around 5 mph becoming calm in the afternoon. Chance of precipitation is 60%.
Tuesday Night
 
 Showers. The rain could be heavy at times. Low around 57. East wind 5 to 10 mph, with gusts as high as 20 mph. Chance of precipitation is 90%. New precipitation amounts between 1 and 2 inches possible.
Wednesday
 
 Showers, with thunderstorms also possible after 10am. Some of the storms could produce heavy rainfall. High near 63. Light and variable wind becoming south 5 to 10 mph in the morning. Winds could gust as high as 20 mph. Chance of precipitation is 100%. New rainfall amounts between 2 and 3 inches possible.
Wednesday Night
 
 Showers and possibly a thunderstorm. Some of the storms could produce heavy rainfall. Low around 54. Southwest wind 5 to 10 mph becoming light and variable. Chance of precipitation is 100%. New rainfall amounts between a quarter and half of an inch possible.
Christmas Day
 
 Showers. High near 62. Chance of precipitation is 80%.
Thursday Night
 
 Showers. Low around 51. Chance of precipitation is 90%.
Friday
 
 Showers. Mostly cloudy, with a high near 60.
Friday Night
 
 Showers likely, mainly before 10pm. Mostly cloudy, with a low around 44.
Saturday
 
 A slight chance of showers. Partly sunny, with a high near 61.
Saturday Night
 
 A slight chance of showers. Partly cloudy, with a low around 42.
Sunday
 
 Sunny, with a high near 65.
Sunday Night
 
 Partly cloudy, with a low around 44.
Monday
 
 A slight chance of showers. Mostly sunny, with a high near 68.

 

Forecast from NOAA-NWS for Ontario International Arpt CA.