Castro Valley · first 14 days — live forecast · rest of month — climate corridor
🗺️ 14-day forecast map
Castro Valley & neighbors — hit play
Every city on the map carries real forecast data from the same models as its city page, refreshed several times a day. The icon is the day's overall look; the number is the afternoon high.
Next 14 days at a glance
from the model forecast
Hottest day
95°
Mon, Sep 7
Coldest night
52°
Mon, Aug 31
Days with precip
0 / 14
of 14 forecast days
Nicest day
Mon, Aug 31
mild, dry, light wind
The next 4 weekends
plan ahead
Sat 29 – Sun 30 Aug
80° 53°
9% precip chance
Sat 5 – Sun 6 Sep
89° 56°
1% precip chance
Sat 12 – Sun 13 Sep
74° 50°
typical range
Sat 19 – Sun 20 Sep
77° 49°
typical range
30 days — Castro Valley
14 forecast + 16 climatology
Tue · Today Mostly cloudy
77°57°22%⌄
Wind6 mph SW
Gusts15 mph
UV index9 – Very high
Precip chance22%
Sunrise06:32
Sunset19:48
Wed · Tomorrow Sunny
87°60°3%⌄
Wind8 mph SW
Gusts18 mph
UV index9 – Very high
Precip chance3%
Sunrise06:33
Sunset19:46
Thursday 27/8 Sunny
88°59°3%⌄
Wind9 mph SW
Gusts21 mph
UV index9 – Very high
Precip chance3%
Sunrise06:34
Sunset19:45
Friday 28/8 Sunny
82°56°4%⌄
Wind8 mph SW
Gusts12 mph
UV index7 – High
Precip chance4%
Sunrise06:35
Sunset19:43
Saturday 29/8 Sunny
80°54°5%⌄
Wind9 mph W
Gusts13 mph
UV index7 – High
Precip chance5%
Sunrise06:36
Sunset19:42
Sunday 30/8 Sunny
71°53°9%⌄
Wind9 mph SW
Gusts12 mph
UV index6 – High
Precip chance9%
Sunrise06:36
Sunset19:41
Monday 31/8 Sunny
69°52°5%⌄
Wind9 mph SW
Gusts11 mph
UV index6 – High
Precip chance5%
Sunrise06:37
Sunset19:39
Tuesday 1/9 Mostly cloudy
77°52°9%⌄
Wind7 mph SW
Gusts18 mph
UV index6 – High
Precip chance9%
Sunrise06:38
Sunset19:38
Wednesday 2/9 Mostly cloudy
87°59°10%⌄
Wind5 mph NE
Gusts10 mph
UV index7 – High
Precip chance10%
Sunrise06:39
Sunset19:36
Thursday 3/9 Mostly cloudy
93°67°9%⌄
Wind6 mph W
Gusts17 mph
UV index7 – High
Precip chance9%
Sunrise06:40
Sunset19:35
Friday 4/9 Mostly cloudy
89°61°4%⌄
Wind7 mph W
Gusts14 mph
UV index8 – Very high
Precip chance4%
Sunrise06:41
Sunset19:33
Saturday 5/9 Sunny
87°56°1%⌄
Wind6 mph N
Gusts15 mph
UV index8 – Very high
Precip chance1%
Sunrise06:41
Sunset19:32
Sunday 6/9 Sunny
89°60°0%⌄
Wind10 mph N
Gusts15 mph
UV index8 – Very high
Precip chance0%
Sunrise06:42
Sunset19:30
Monday 7/9 Sunny
95°63°0%⌄
Wind8 mph W
Gusts16 mph
UV index8 – Very high
Precip chance0%
Sunrise06:43
Sunset19:29
Tuesday 8/9 Light rain (climatological)
77°53°1.6 mm⌄
Day≈72–83°
Night≈47–58°
Precip≈0.6 in / September
(climatological)Typical range for these dates · 1991–2020
Wednesday 9/9 Partly cloudy (climatological)
82°56°20%⌄
Day≈77–88°
Night≈50–61°
Precip≈0.6 in / September
(climatological)Typical range for these dates · 1991–2020
Thursday 10/9 Partly cloudy (climatological)
79°53°20%⌄
Day≈73–84°
Night≈48–59°
Precip≈0.6 in / September
(climatological)Typical range for these dates · 1991–2020
Friday 11/9 Light rain (climatological)
81°55°1.5 mm⌄
Day≈76–87°
Night≈49–60°
Precip≈0.6 in / September
(climatological)Typical range for these dates · 1991–2020
Saturday 12/9 Partly cloudy (climatological)
74°50°20%⌄
Day≈68–79°
Night≈45–56°
Precip≈0.6 in / September
(climatological)Typical range for these dates · 1991–2020
Sunday 13/9 Partly cloudy (climatological)
73°50°20%⌄
Day≈67–78°
Night≈44–55°
Precip≈0.6 in / September
(climatological)Typical range for these dates · 1991–2020
Monday 14/9 Light rain (climatological)
72°49°1.3 mm⌄
Day≈67–77°
Night≈44–55°
Precip≈0.6 in / September
(climatological)Typical range for these dates · 1991–2020
Tuesday 15/9 Partly cloudy (climatological)
75°51°20%⌄
Day≈70–81°
Night≈46–57°
Precip≈0.6 in / September
(climatological)Typical range for these dates · 1991–2020
Wednesday 16/9 Partly cloudy (climatological)
82°55°20%⌄
Day≈76–87°
Night≈50–60°
Precip≈0.6 in / September
(climatological)Typical range for these dates · 1991–2020
Thursday 17/9 Light rain (climatological)
81°55°2.0 mm⌄
Day≈76–87°
Night≈49–60°
Precip≈0.6 in / September
(climatological)Typical range for these dates · 1991–2020
Friday 18/9 Partly cloudy (climatological)
77°52°20%⌄
Day≈71–82°
Night≈47–58°
Precip≈0.6 in / September
(climatological)Typical range for these dates · 1991–2020
Saturday 19/9 Partly cloudy (climatological)
77°53°20%⌄
Day≈72–83°
Night≈47–58°
Precip≈0.6 in / September
(climatological)Typical range for these dates · 1991–2020
Sunday 20/9 Light rain (climatological)
72°49°1.6 mm⌄
Day≈67–77°
Night≈44–55°
Precip≈0.6 in / September
(climatological)Typical range for these dates · 1991–2020
Monday 21/9 Partly cloudy (climatological)
71°49°20%⌄
Day≈66–76°
Night≈43–54°
Precip≈0.6 in / September
(climatological)Typical range for these dates · 1991–2020
Tuesday 22/9 Partly cloudy (climatological)
79°54°20%⌄
Day≈74–85°
Night≈48–59°
Precip≈0.6 in / September
(climatological)Typical range for these dates · 1991–2020
Wednesday 23/9 Light rain (climatological)
81°55°0.9 mm⌄
Day≈76–87°
Night≈49–60°
Precip≈0.6 in / September
(climatological)Typical range for these dates · 1991–2020
How does a 30-day outlook work?
The first 14 days are a live model forecast. The back half of the month shows the typical range for those dates — useful for planning, not a literal prediction.
First 14 days: a real forecast, blended from NBM, ECMWF and GFS runs. Trust it most inside three days; by the second week treat it as a lean, not a promise.
Rest of the month: past day 14 we stop pretending to forecast and switch to the climate corridor — the range those dates have produced over three decades computed directly for Castro Valley, with mild week-to-week wiggle.
Good question for this page: "Is late August usually humid in Chicago?" Bad question: "Do I need an umbrella on the 29th?" — three weeks out no one knows, and that's the honest answer.