Upper Lake, CA Weather Forecast
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Upper Lake Weather Forecast
| TODAY | TONIGHT | SUNDAY | SUNDAY NIGHT | MONDAY | MONDAY NIGHT | TUESDAY | TUESDAY NIGHT | WEDNESDAY | THURSDAY | THURSDAY NIGHT | FRIDAY |
| Sunny | Partly Cloudy | Mostly Cloudy | Mostly Cloudy | Sunny | Mostly Clear | Clear | Clear | Mostly Clear | Mostly Clear | Partly Cloudy | Partly Cloudy |
| Hi: 88°FHi: 31°C | Lo: 60°FLo: 16°C | Hi: 87°FHi: 31°C | Lo: 61°FLo: 16°C | Hi: 88°FHi: 31°C | Lo: 60°FLo: 16°C | Hi: 89°FHi: 32°C Lo: 61°FLo: 16°C | Hi: 89°FHi: 32°C Lo: 61°FLo: 16°C | Hi: 90°FHi: 32°C Lo: 62°FLo: 17°C | Hi: 90°FHi: 32°C Lo: 62°FLo: 17°C | Hi: 87°FHi: 31°C Lo: 62°FLo: 17°C | Hi: 87°FHi: 31°C Lo: 62°FLo: 17°C |
POP = Probability of Precipitation.
Weather Outlook Updated: 136 AM PDT Sat Sep 19 2026 

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Issued: 1215 AM PDT Sat Sep 19 2026
Key Messages
- Warmer and drier interior temperatures into the weekend with highs in the 90s by Sunday.
- A shallow but strong marine layer forming close to shore with persistent marine clouds.
- Similar warm and dry conditions early next week with potential clearing near shore by Monday.
Discussion
...High pressure will continue to grow through the weekend. Extensive marine stratus remains along the coast overnight and should last through most of the weekend with clearing each afternoon not likely. Dayt...
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