Current Conditions

Rosemont, California

84°F29°C
Hot

Wind

NNW 5 mph8 km/h

Humidity

28%

Cloud Cover

79%

As of Tuesday, September 8, 2026 at 8:00 PM PDT

Today's Outlook

Night

Mostly cloudy, with a low around 67°F20°C. Light wind from the NNW around 4 mph6 km/h.

7-Day Forecast

DayConditionHigh (°F)Low (°F)Precip (mm)Cloud Cover (%)Wind (mph)
HotHigh 100°F38°CLow 67°F20°CPrecip 0 in0 mmCloud 71%Wind NW 5 mph8 km/hWednesday: Mostly cloudy and hot, with a high of 100°F38°C and morning low of 71°F22°C. Breezy from the NW at 6 to 7 mph9 to 11 km/h. Heat risk in the afternoon. Wednesday Night: Mostly cloudy, with a low around 67°F20°C. Light wind from the NNW around 4 mph6 km/h.
HotHigh 101°F38°CLow 72°F22°CPrecip 0 in0 mmCloud 33%Wind SSW 4 mph7 km/hThursday: Partly cloudy and hot, with a high of 101°F38°C and morning low of 74°F23°C. Breezy from the SW at 4 to 7 mph7 to 11 km/h. Heat risk in the afternoon. Thursday Night: Partly cloudy, with a low around 72°F22°C. Breezy from the S at 5 to 8 mph8 to 12 km/h.
ClearHigh 92°F33°CLow 69°F21°CPrecip 0 in0 mmCloud 2%Wind SSW 7 mph11 km/hFriday: Mostly clear and hot, with a high of 92°F33°C and morning low of 70°F21°C. Breezy from the SSW at 7 to 8 mph11 to 13 km/h. Dry air. Friday Night: Mostly clear, with a low around 69°F21°C. Breezy from the S at 7 mph11 km/h.
ClearHigh 86°F30°CLow 63°F17°CPrecip 0 in0 mmCloud 6%Wind SSW 8 mph13 km/hSaturday: Mostly clear and hot, with a high of 86°F30°C and morning low of 65°F18°C. Breezy from the SSW at 9 to 11 mph15 to 17 km/h. Dry air. Saturday Night: Mostly clear, with a low around 63°F17°C. Breezy from the S at 7 to 9 mph12 to 14 km/h.
ClearHigh 86°F30°CLow 59°F15°CPrecip 0 in0 mmCloud 6%Wind WNW 6 mph9 km/hSunday: Mostly clear and warm, with a high of 86°F30°C and morning low of 64°F18°C. Breezy from the NW at 6 to 7 mph10 to 11 km/h. Dry air. Sunday Night: Mostly clear, with a low around 59°F15°C. Light wind from the SW around 5 mph8 km/h.
ClearHigh 88°F31°CLow 59°F15°CPrecip 0 in0 mmCloud 6%Wind WSW 4 mph6 km/hMonday: Mostly clear and hot, with a high of 88°F31°C and morning low of 62°F17°C. Light wind from the WNW around 4 mph6 km/h. Dry air. Monday Night: Mostly clear, with a low around 59°F15°C. Light wind from the SW around 4 mph7 km/h.
ClearHigh 86°F30°CLow 59°F15°CPrecip 0 in0 mmCloud 13%Wind SSW 5 mph8 km/hTuesday: Mostly clear and hot, with a high of 86°F30°C and morning low of 63°F17°C. Light wind from the SW around 5 mph7 km/h. Dry air. Tuesday Night: Mostly clear, with a low around 59°F15°C. Light wind from the SSW around 5 mph8 km/h.

15-Day Forecast

Day High Low Precip Cloud Cover Condition Wind
WednesdaySep 9100°F38°C67°F20°C0 in0 mm· —71%HotNW 5 mph8 km/h
ThursdaySep 10101°F38°C72°F22°C0 in0 mm· —33%HotSSW 4 mph7 km/h
FridaySep 1192°F33°C69°F21°C0 in0 mm· —2%ClearSSW 7 mph11 km/h
SaturdaySep 1286°F30°C63°F17°C0 in0 mm· —6%ClearSSW 8 mph13 km/h
SundaySep 1386°F30°C59°F15°C0 in0 mm· —6%ClearWNW 6 mph9 km/h
MondaySep 1488°F31°C59°F15°C0 in0 mm· —6%ClearWSW 4 mph6 km/h
TuesdaySep 1586°F30°C59°F15°C0 in0 mm· —13%ClearSSW 5 mph8 km/h
WednesdaySep 1685°F29°C58°F15°C0 in0 mm· —11%ClearSSW 5 mph8 km/h
ThursdaySep 1786°F30°C58°F14°C0 in0 mm· —12%ClearSW 4 mph7 km/h
FridaySep 1886°F30°C59°F15°C0 in0.1 mm· 3%19%ClearSW 4 mph7 km/h
SaturdaySep 1986°F30°C60°F15°C0 in0 mm· —20%ClearSW 5 mph7 km/h
SundaySep 2086°F30°C60°F15°C0.01 in0.2 mm· 2%22%ClearSW 4 mph7 km/h
MondaySep 2187°F31°C60°F16°C0.01 in0.2 mm· 2%17%ClearSW 5 mph7 km/h
TuesdaySep 2288°F31°C61°F16°C0.02 in0.4 mm· 3%20%ClearSW 5 mph8 km/h
WednesdaySep 2388°F31°C61°F16°C0 in0.1 mm· 2%21%ClearSW 4 mph7 km/h

Nearby Cities

About This Forecast

This forecast is powered by WeatherMesh, the world's most advanced and accurate weather model powered by AI. WeatherMesh is built on proprietary data from WindBorne's Global Sounding Balloon constellation — the world's largest fleet of autonomous, long-duration weather balloons — collecting observations across 100% of Earth, including over oceans and remote regions where no other data exists.

WeatherMesh consistently outperforms legacy models in independent benchmarks. View Benchmarks →

Access WeatherMesh forecasts programmatically via our API. API Documentation →

How to Access Weather Forecasts

PatternExampleDescription
/weather/{country}/{city}//weather/united-states/san-francisco/City forecast (canonical URL)
/weather/{city}//weather/tokyo/Shorthand — redirects to most populous match
/weather/{country}/{region}/{city}//weather/united-states/california/san-francisco/With region — redirects to canonical
/weather/nearby?lat={lat}&lon={lon}/weather/nearby?lat=48.1&lon=11.5Find nearest city by coordinates
/weather/{country}//weather/germany/Country index — all cities by region

Country and city names use lowercase slugs with hyphens (e.g. united-states, san-francisco). Arbitrary city names are supported — if not in our database, we geocode the name and serve the forecast for that location.

For programmatic access, use theWindBorne Forecast APIwhich returns structured JSON for any coordinates worldwide.

Coordinates: 38.5519°N, 121.3647°W·Elevation: 15m·Timezone: America/Los_Angeles·Population: 22,681