Current Conditions

Castro Valley, California

64°F18°C

Drizzle

Wind

WSW 7 mph11 km/h

Humidity

76%

Cloud Cover

38%

As of Wednesday, September 2, 2026 at 7:12 PM PDT

Today's Outlook

Night

Mostly cloudy, with a low around 57°F14°C. Breezy from the SW at 5 to 7 mph8 to 11 km/h. 14% chance of drizzle in the evening.

7-Day Forecast

Condition	High (°F)	Low (°F)	Precip (mm)	Cloud Cover (%)	Wind (mph)
Drizzle	High 72°F22°C	Low 57°F14°C	Precip 0.01 in0.3 mm14%	Cloud 70%	Wind SW 7 mph11 km/h	Thursday: Mostly cloudy and warm, with a high of 72°F22°C and morning low of 61°F16°C. Breezy from the SW at 8 to 10 mph13 to 16 km/h. Thursday Night: Mostly cloudy, with a low around 57°F14°C. Breezy from the SW at 5 to 7 mph8 to 11 km/h. 14% chance of drizzle in the evening.
Drizzle	High 72°F22°C	Low 59°F15°C	Precip 0.01 in0.2 mm12%	Cloud 34%	Wind W 5 mph9 km/h	Friday: Partly cloudy and warm, with a high of 72°F22°C and morning low of 61°F16°C. Breezy from the W at 6 to 9 mph10 to 14 km/h. Friday Night: Partly cloudy, with a low around 59°F15°C. Light wind from the W around 4 mph7 km/h. 12% chance of drizzle.
Clear	High 73°F23°C	Low 55°F13°C	Precip 0 in0 mm—	Cloud 26%	Wind WSW 5 mph9 km/h	Saturday: Partly cloudy and warm, with a high of 73°F23°C and morning low of 59°F15°C. Breezy from the WSW at 6 to 9 mph10 to 15 km/h. Saturday Night: Mostly clear, with a low around 55°F13°C. Light wind from the WSW around 4 mph7 km/h.
Clear	High 72°F22°C	Low 56°F13°C	Precip 0 in0 mm—	Cloud 23%	Wind WSW 7 mph11 km/h	Sunday: Mostly clear and warm, with a high of 72°F22°C and morning low of 58°F15°C. Breezy from the WSW at 9 to 11 mph14 to 17 km/h. Sunday Night: Partly cloudy, with a low around 56°F13°C. Breezy from the WSW at 5 to 7 mph8 to 11 km/h.
Clear	High 79°F26°C	Low 54°F12°C	Precip 0 in0 mm—	Cloud 17%	Wind WNW 4 mph6 km/h	Monday: Mostly clear and warm, with a high of 79°F26°C and morning low of 59°F15°C. Breezy from the NW at 4 to 7 mph7 to 11 km/h. Monday Night: Mostly clear, with a low around 54°F12°C. Light wind from the WSW around 4 mph6 km/h.
Clear	High 82°F28°C	Low 57°F14°C	Precip 0 in0 mm—	Cloud 32%	Wind WSW 4 mph6 km/h	Tuesday: Partly cloudy and warm, with a high of 82°F28°C and morning low of 60°F16°C. Breezy from the W at 4 to 7 mph7 to 11 km/h. Tuesday Night: Partly cloudy, with a low around 57°F14°C. Light wind from the SW around 3 mph6 km/h.
Clear	High 83°F29°C	Low 60°F16°C	Precip 0.01 in0.2 mm3%	Cloud 32%	Wind WSW 4 mph7 km/h	Wednesday: Partly cloudy and warm, with a high of 83°F29°C and morning low of 64°F18°C. Light wind from the W around 5 mph7 km/h. Wednesday Night: Partly cloudy, with a low around 60°F16°C. Light wind from the SW around 4 mph6 km/h.

15-Day Forecast

	Day	High	Low	Precip	Cloud Cover	Condition	Wind
	ThursdaySep 3	72°F22°C	57°F14°C	0.01 in0.3 mm· 14%	70%	Drizzle	SW 7 mph11 km/h
DayMostly cloudy and warm, with a high of 72°F22°C and morning low of 61°F16°C. Breezy from the SW at 8 to 10 mph13 to 16 km/h. NightMostly cloudy, with a low around 57°F14°C. Breezy from the SW at 5 to 7 mph8 to 11 km/h. 14% chance of drizzle in the evening.
	FridaySep 4	72°F22°C	59°F15°C	0.01 in0.2 mm· 12%	34%	Drizzle	W 5 mph9 km/h
DayPartly cloudy and warm, with a high of 72°F22°C and morning low of 61°F16°C. Breezy from the W at 6 to 9 mph10 to 14 km/h. NightPartly cloudy, with a low around 59°F15°C. Light wind from the W around 4 mph7 km/h. 12% chance of drizzle.
	SaturdaySep 5	73°F23°C	55°F13°C	0 in0 mm· —	26%	Clear	WSW 5 mph9 km/h
DayPartly cloudy and warm, with a high of 73°F23°C and morning low of 59°F15°C. Breezy from the WSW at 6 to 9 mph10 to 15 km/h. NightMostly clear, with a low around 55°F13°C. Light wind from the WSW around 4 mph7 km/h.
	SundaySep 6	72°F22°C	56°F13°C	0 in0 mm· —	23%	Clear	WSW 7 mph11 km/h
DayMostly clear and warm, with a high of 72°F22°C and morning low of 58°F15°C. Breezy from the WSW at 9 to 11 mph14 to 17 km/h. NightPartly cloudy, with a low around 56°F13°C. Breezy from the WSW at 5 to 7 mph8 to 11 km/h.
	MondaySep 7	79°F26°C	54°F12°C	0 in0 mm· —	17%	Clear	WNW 4 mph6 km/h
DayMostly clear and warm, with a high of 79°F26°C and morning low of 59°F15°C. Breezy from the NW at 4 to 7 mph7 to 11 km/h. NightMostly clear, with a low around 54°F12°C. Light wind from the WSW around 4 mph6 km/h.
	TuesdaySep 8	82°F28°C	57°F14°C	0 in0 mm· —	32%	Clear	WSW 4 mph6 km/h
DayPartly cloudy and warm, with a high of 82°F28°C and morning low of 60°F16°C. Breezy from the W at 4 to 7 mph7 to 11 km/h. NightPartly cloudy, with a low around 57°F14°C. Light wind from the SW around 3 mph6 km/h.
	WednesdaySep 9	83°F29°C	60°F16°C	0.01 in0.2 mm· 3%	32%	Clear	WSW 4 mph7 km/h
DayPartly cloudy and warm, with a high of 83°F29°C and morning low of 64°F18°C. Light wind from the W around 5 mph7 km/h. NightPartly cloudy, with a low around 60°F16°C. Light wind from the SW around 4 mph6 km/h.
	ThursdaySep 10	83°F28°C	62°F17°C	0.02 in0.4 mm· 3%	29%	Clear	WSW 5 mph7 km/h
DayPartly cloudy and warm, with a high of 83°F28°C and morning low of 64°F18°C. Breezy from the W at 5 to 8 mph8 to 12 km/h. NightPartly cloudy, with a low around 62°F17°C. Light wind from the SW around 4 mph6 km/h.
	FridaySep 11	79°F26°C	61°F16°C	0.01 in0.2 mm· 4%	31%	Clear	WSW 6 mph9 km/h
DayPartly cloudy and warm, with a high of 79°F26°C and morning low of 64°F18°C. Breezy from the WSW at 7 to 9 mph11 to 14 km/h. NightPartly cloudy, with a low around 61°F16°C. Light wind from the SW around 5 mph8 km/h.
	SaturdaySep 12	77°F25°C	59°F15°C	0 in0.1 mm· 3%	36%	Clear	WSW 6 mph9 km/h
DayPartly cloudy and warm, with a high of 77°F25°C and morning low of 61°F16°C. Breezy from the WSW at 7 to 8 mph11 to 14 km/h. NightPartly cloudy, with a low around 59°F15°C. Light wind from the SW around 5 mph8 km/h.
	SundaySep 13	78°F25°C	59°F15°C	0.02 in0.4 mm· 6%	35%	Clear	WSW 5 mph8 km/h
DayPartly cloudy and warm, with a high of 78°F25°C and morning low of 61°F16°C. Breezy from the W at 6 to 8 mph9 to 13 km/h. NightPartly cloudy, with a low around 59°F15°C. Light wind from the SW around 4 mph7 km/h.
	MondaySep 14	78°F25°C	59°F15°C	0.02 in0.6 mm· 5%	29%	Clear	WSW 5 mph8 km/h
DayPartly cloudy and warm, with a high of 78°F25°C and morning low of 61°F16°C. Breezy from the W at 6 to 8 mph9 to 13 km/h. NightPartly cloudy, with a low around 59°F15°C. Light wind from the SW around 4 mph7 km/h.
	TuesdaySep 15	79°F26°C	59°F15°C	0.02 in0.5 mm· 4%	27%	Clear	WSW 5 mph7 km/h
DayPartly cloudy and warm, with a high of 79°F26°C and morning low of 61°F16°C. Breezy from the W at 5 to 7 mph8 to 12 km/h. NightPartly cloudy, with a low around 59°F15°C. Light wind from the SW around 4 mph6 km/h.
	WednesdaySep 16	80°F27°C	60°F15°C	0.01 in0.3 mm· 4%	27%	Clear	WSW 5 mph7 km/h
DayPartly cloudy and warm, with a high of 80°F27°C and morning low of 62°F17°C. Breezy from the W at 5 to 7 mph8 to 12 km/h. NightPartly cloudy, with a low around 60°F15°C. Light wind from the SW around 4 mph6 km/h.
	ThursdaySep 17	80°F27°C	60°F16°C	0.01 in0.2 mm· 3%	30%	Clear	WSW 5 mph7 km/h
DayPartly cloudy and warm, with a high of 80°F27°C and morning low of 62°F17°C. Breezy from the W at 5 to 7 mph8 to 11 km/h. NightPartly cloudy, with a low around 60°F16°C. Light wind from the SW around 3 mph5 km/h.

Nearby Cities

Ashland2 mi2 km Hayward2 mi3 km San Lorenzo3 mi5 km San Leandro4 mi7 km Union City8 mi12 km Dublin8 mi13 km

About This Forecast

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Coordinates: 37.6941°N, 122.0863°W·Elevation: 50m·Timezone: America/Los_Angeles·Population: 61,388