National Weather Service Forecast for: Rancho Cucamonga CA
Issued by: National Weather Service San Diego, CA
Updated: 8:38 pm PDT Jun 29, 2026
 
Overnight

Overnight: Patchy drizzle after 2am. Patchy fog before 2am. Otherwise, mostly cloudy, with a low around 57. Southwest wind around 5 mph becoming northwest.
Patchy
Drizzle and
Patchy Fog
 Tuesday

Tuesday: Patchy drizzle before 11am. Mostly cloudy through mid morning, then gradual clearing, with a high near 77. Southwest wind 5 to 10 mph increasing to 10 to 15 mph in the afternoon. Winds could gust as high as 20 mph.
Patchy
Drizzle then
Sunny
 Tuesday
Night
Tuesday Night: Increasing clouds, with a low around 57. Southwest wind 5 to 10 mph becoming northwest after midnight. Winds could gust as high as 20 mph.
Increasing
Clouds
 Wednesday

Wednesday: Patchy fog before 11am. Otherwise, mostly cloudy through mid morning, then gradual clearing, with a high near 80. Light and variable wind becoming southwest 10 to 15 mph in the afternoon. Winds could gust as high as 20 mph.
Patchy Fog
then Sunny
 Wednesday
Night
Wednesday Night: Mostly clear, with a low around 56. Southwest wind 10 to 15 mph becoming light west after midnight. Winds could gust as high as 20 mph.
Mostly Clear

 Thursday

Thursday: Sunny, with a high near 82.
Sunny

 Thursday
Night
Thursday Night: Mostly clear, with a low around 58.
Mostly Clear

 Friday

Friday: Sunny, with a high near 85.
Sunny

 Friday
Night
Friday Night: Mostly clear, with a low around 60.
Mostly Clear
Lo 57 °F Hi 77 °F Lo 57 °F Hi 80 °F Lo 56 °F Hi 82 °F Lo 58 °F Hi 85 °F Lo 60 °F

 

Overnight
 
 Patchy drizzle after 2am. Patchy fog before 2am. Otherwise, mostly cloudy, with a low around 57. Southwest wind around 5 mph becoming northwest.
Tuesday
 
 Patchy drizzle before 11am. Mostly cloudy through mid morning, then gradual clearing, with a high near 77. Southwest wind 5 to 10 mph increasing to 10 to 15 mph in the afternoon. Winds could gust as high as 20 mph.
Tuesday Night
 
 Increasing clouds, with a low around 57. Southwest wind 5 to 10 mph becoming northwest after midnight. Winds could gust as high as 20 mph.
Wednesday
 
 Patchy fog before 11am. Otherwise, mostly cloudy through mid morning, then gradual clearing, with a high near 80. Light and variable wind becoming southwest 10 to 15 mph in the afternoon. Winds could gust as high as 20 mph.
Wednesday Night
 
 Mostly clear, with a low around 56. Southwest wind 10 to 15 mph becoming light west after midnight. Winds could gust as high as 20 mph.
Thursday
 
 Sunny, with a high near 82.
Thursday Night
 
 Mostly clear, with a low around 58.
Friday
 
 Sunny, with a high near 85.
Friday Night
 
 Mostly clear, with a low around 60.
Independence Day
 
 Mostly sunny, with a high near 88.
Saturday Night
 
 Mostly clear, with a low around 61.
Sunday
 
 Sunny, with a high near 88.
Sunday Night
 
 Mostly clear, with a low around 62.
Monday
 
 Sunny, with a high near 90.

 

Forecast from NOAA-NWS for Rancho Cucamonga CA.