National Weather Service Forecast for: Ontario International Arpt CA
Issued by: National Weather Service San Diego, CA
Updated: 12:29 am PDT Jun 22, 2026
 
Overnight

Overnight: Patchy fog after 5am. Otherwise, partly cloudy, with a low around 60. Southwest wind around 5 mph becoming calm.
Patchy Fog
 Monday

Monday: Patchy fog before 8am. Otherwise, sunny, with a high near 89. Light and variable wind becoming west 10 to 15 mph in the afternoon. Winds could gust as high as 20 mph.
Patchy Fog
then Sunny
 Monday
Night
Monday Night: Patchy fog after 5am. Otherwise, mostly clear, with a low around 62. West wind 5 to 10 mph becoming light southwest after midnight. Winds could gust as high as 20 mph.
Clear then
Patchy Fog
 Tuesday

Tuesday: Patchy fog before 8am. Otherwise, sunny, with a high near 94. Light southwest wind becoming west 10 to 15 mph in the afternoon. Winds could gust as high as 20 mph.
Patchy Fog
then Sunny
 Tuesday
Night
Tuesday Night: Mostly clear, with a low around 66. West wind 5 to 10 mph becoming light after midnight. Winds could gust as high as 20 mph.
Mostly Clear
 Wednesday

Wednesday: Mostly sunny, with a high near 95.
Mostly Sunny
 Wednesday
Night
Wednesday Night: Mostly clear, with a low around 63.
Mostly Clear
 Thursday

Thursday: Sunny, with a high near 93.
Sunny
 Thursday
Night
Thursday Night: Mostly clear, with a low around 61.
Mostly Clear
Lo 60 °F Hi 89 °F Lo 62 °F Hi 94 °F Lo 66 °F Hi 95 °F Lo 63 °F Hi 93 °F Lo 61 °F

Air Quality Alert
 

Overnight
 
 Patchy fog after 5am. Otherwise, partly cloudy, with a low around 60. Southwest wind around 5 mph becoming calm.
Monday
 
 Patchy fog before 8am. Otherwise, sunny, with a high near 89. Light and variable wind becoming west 10 to 15 mph in the afternoon. Winds could gust as high as 20 mph.
Monday Night
 
 Patchy fog after 5am. Otherwise, mostly clear, with a low around 62. West wind 5 to 10 mph becoming light southwest after midnight. Winds could gust as high as 20 mph.
Tuesday
 
 Patchy fog before 8am. Otherwise, sunny, with a high near 94. Light southwest wind becoming west 10 to 15 mph in the afternoon. Winds could gust as high as 20 mph.
Tuesday Night
 
 Mostly clear, with a low around 66. West wind 5 to 10 mph becoming light after midnight. Winds could gust as high as 20 mph.
Wednesday
 
 Mostly sunny, with a high near 95.
Wednesday Night
 
 Mostly clear, with a low around 63.
Thursday
 
 Sunny, with a high near 93.
Thursday Night
 
 Mostly clear, with a low around 61.
Friday
 
 Sunny, with a high near 90.
Friday Night
 
 Mostly clear, with a low around 60.
Saturday
 
 Sunny, with a high near 88.
Saturday Night
 
 Increasing clouds, with a low around 59.
Sunday
 
 Partly sunny, then gradually becoming sunny, with a high near 81.

 

Forecast from NOAA-NWS for Ontario International Arpt CA.