The temperatures in Castro in September are quite cold with temperatures between 5°C and 11°C, warm clothes are a must.
You can expect rain for roughly half of the month of September in Castro. We’re expecting roughly 8 to 15 days of rain, so your rubber boots and umbrella are going to see plenty of use this month if you’re keen on staying dry.
Our weather forecast can give you a great sense of what weather to expect in Castro in September 2026.
If you’re planning to visit Castro in the near future, we highly recommend that you review the 14 day weather forecast for Castro before you arrive.
Temperatures
11° / 5°
Rainy Days
10
Snowy Days
0
Dry Days
20
Rainfall
182
mm
Sun Hours
7.3
Hrs
