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Alta Loma Weather Forecast
| TONIGHT | WEDNESDAY | WEDNESDAY NIGHT | THURSDAY | THURSDAY NIGHT | FRIDAY | FRIDAY NIGHT | SATURDAY | SATURDAY NIGHT | SUNDAY | SUNDAY NIGHT | MONDAY |
 |  |  |  |  |  |  |  | | |  | |
| Patchy Fog | Chance of Showers | Chance of T-Storm | Chance of T-Storm | Chance of Showers | Partly Cloudy | Mostly Clear | Sunny | Clear | Mostly Sunny | Partly Cloudy | Partly Cloudy |
| Lo: 58°FLo: 14°C | Hi: 78°FHi: 26°C | Lo: 58°FLo: 14°C | Hi: 68°FHi: 20°C | Lo: 52°FLo: 11°C | Hi: 72°FHi: 22°C | Lo: 52°FLo: 11°C | Hi: 77°FHi: 25°C | Lo: 55°FLo: 13°C | Hi: 79°FHi: 26°C | Lo: 57°FLo: 14°C | Hi: 81°FHi: 27°C |
| POP: 50% | POP: 70% | POP: 40% |
POP = Probability of Precipitation.
Weather Outlook Updated: 1150 AM PDT Tue Oct 20 2026 
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Issued: 1055 PM PDT Tue Oct 20 2026
Discussion
...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES...
...UPDATED AVIATION DISCUSSION...
The low pressure system west of Point Conception continues to move south before turning east Wednesday. It will move through SoCal on Thursday and Friday. It will bring further cooling, a deepening marine layer with more low clouds, and widespread precipitation. Showers could spread into coastal areas during the afternoon o...