The biggest temperature swing occurs between October and November, with a change of 4°C.
| Month | Low Temperature | High Temperature | Category |
|---|---|---|---|
| January | | | cool |
| February | | | cool |
| March | | | mild |
| April | | | mild |
| May | | | mild |
| June | | | mild |
| July | | | mild |
| August | | | mild |
| September | | | warm |
| October | | | mild |
| November | | | mild |
| December | | | cool |
⚠️ High UV Alert: March, April, May, June, July, August, September require serious sun protection.
Daylight varies from 9.6 hours in December (winter) to 14.7 hours in June (summer), which is a difference of 5.1 hours.
Northern Hemisphere seasons shape the weather patterns throughout the year. Here's what to expect in each season:
Click any month for detailed weather information and packing advice.
Get personalized month rankings based on weather comfort, outdoor activity suitability, and seasonal conditions.
View Best Time to VisitThe best months to visit San Francisco depend on your preferences. For warm weather, September is typically the warmest month. For dry conditions, July, August, September tend to have the least rainfall. Consider your priorities—whether you prefer warmer temperatures, drier weather, or longer daylight hours.
September is typically the warmest month in San Francisco, with average high temperatures reaching around 22°C (72°F). This is peak summer weather, ideal for outdoor activities and sightseeing.
January is usually the coldest month, with average low temperatures dropping to around 7°C (45°F). Pack warm layers if visiting during this time, especially for evening activities.
December typically sees the most rainfall in San Francisco, averaging around 137mm (5.4 inches). It's wise to pack waterproof layers and have some indoor backup plans if you're visiting during this month.
July is typically the driest month, with average rainfall of just 0mm (0.0 inches). This makes it an excellent time for outdoor exploration and activities with minimal risk of rain disruption.
Temperatures in San Francisco range from average lows of 10°C (50°F) to highs of 18°C (64°F). This variation means you'll want to pack differently depending on when you visit—layers are key for adapting to the seasonal changes.
Yes, sun protection is important in San Francisco. UV levels can reach 8 during peak months, which is considered very high. Pack sunscreen (SPF 30+), sunglasses, and a hat, especially if you'll be outdoors for extended periods.