Yes
you do need a jacket based on the weather in Castro Valley, CA 94552, USA 1 second ago
Why? Because it's cool. Pleasantly cool, but cool!
54°F12°C & Mostly Cloudy
Wind is 6 mph9 km/h from the West, gusting to 9 mph15 km/h
| July 20 | ||||
| 6am | 54°F12°C | 5 mph9 km/h West | Mostly Cloudy | |
| 7am | 54°F12°C | 4 mph7 km/h Southwest | Mostly Cloudy | |
| 8am | 53°F12°C | 4 mph6 km/h Southwest | Mostly Cloudy | |
| 9am | 53°F11°C | 4 mph6 km/h Southwest | Mostly Cloudy | |
| 10am | 53°F12°C | 4 mph7 km/h Southwest | Mostly Cloudy | |
| 11am | 56°F13°C | 6 mph9 km/h Southwest | Partly Cloudy | |
| 12pm | 59°F15°C | 7 mph11 km/h Southwest | Mostly Clear | |
| 1pm | 62°F17°C | 6 mph10 km/h Southwest | Mostly Clear | |
| 2pm | 65°F18°C | 7 mph11 km/h Southwest | Mostly Clear | |
| 3pm | 67°F20°C | 8 mph13 km/h Southwest | Mostly Clear | |
| 4pm | 69°F21°C | 9 mph14 km/h Southwest | Clear | |
| 5pm | 70°F21°C | 10 mph16 km/h West | Clear | |
| Date | Low | High | Wind | Day | Night |
|---|---|---|---|---|---|
| July 20 | 53°F11°C | 70°F21°C | 8 mph13 km/h from Southwest | Mostly Clear | Mostly Cloudy |
| July 21 | 54°F12°C | 66°F19°C | 11 mph17 km/h from Southwest | Mostly Cloudy | Cloudy |
| July 22 | 55°F13°C | 66°F19°C | 8 mph14 km/h from West | Mostly Cloudy | Mostly Cloudy |
| July 23 | 54°F12°C | 69°F20°C | 8 mph12 km/h from West | Partly Cloudy | Mostly Cloudy |
| July 24 | 55°F13°C | 69°F21°C | 8 mph13 km/h from West | Partly Cloudy | Mostly Cloudy |
| July 25 | 56°F13°C | 70°F21°C | 8 mph13 km/h from West | Partly Cloudy | Mostly Cloudy |
| July 26 | 55°F13°C | 69°F20°C | 8 mph12 km/h from West | Partly Cloudy | Mostly Cloudy |
Yes
Low of 55°F13°C, High of 66°F19°CWind: 11 mph17 km/h
Precipitation: None