The Unique Weather of San Francisco

San Francisco’s weather is as famous as its Golden Gate Bridge—unpredictable, ever-changing, and full of surprises. Unlike the rest of California, where sunshine dominates, the City by the Bay boasts its own microclimate, shaped by the Pacific Ocean, coastal mountains, and the iconic fog that rolls in almost daily. Whether you're a local navigating the city's shifting conditions or a visitor trying to pack smartly, understanding San Francisco’s weather can make all the difference.

The Microclimate Effect

San Francisco isn’t just one city when it comes to weather—it’s a patchwork of microclimates. While one neighborhood basks in sunshine, another just a few miles away might be shrouded in mist. The main reason? The Pacific Ocean and the cold California Current, which send cool air rushing into the Bay. This creates dramatic temperature differences between areas such as:

The Sunset and Richmond Districts: These western neighborhoods are closest to the ocean and are often the foggiest and coolest parts of the city.
Downtown and SOMA: Sheltered by hills, these areas tend to be warmer and sunnier.
The Mission District: Known for its sunny and dry climate, the Mission often enjoys temperatures 5-10 degrees warmer than the western side of the city.
Twin Peaks and Bernal Heights: Elevated areas like these can experience strong winds but also offer stunning views of the ever-changing skies.

The Role of Fog

Fog is perhaps San Francisco’s most well-known weather phenomenon. The famous “Karl the Fog” (as locals have affectionately named it) is a year-round visitor but peaks in the summer. While much of California experiences hot, dry weather in June, July, and August, San Francisco remains cool and misty. This is due to warm inland temperatures pulling in the cool ocean air, forming dense fog that blankets the city—especially in the early mornings and evenings.

Temperature Trends by Season

San Francisco’s climate is classified as Mediterranean, but it doesn’t follow the traditional summer-winter patterns most people expect.

Spring (March-May): Temperatures range from the mid-50s to mid-60s (°F). This is a transitional period where the fog begins to increase, but sunny days are still common.
Summer (June-August): Surprisingly cool compared to inland California, with highs often in the 60s. This is peak fog season, and temperatures can drop sharply in the evenings.
Fall (September-November): Often the warmest and sunniest time of the year, with temperatures occasionally reaching the 70s or even low 80s. Many locals consider September and October to be San Francisco’s “true summer.”
Winter (December-February): The city experiences its rainiest season, but temperatures remain mild, usually between 50-60°F, with occasional colder nights.

What to Wear in San Francisco

The key to dressing for San Francisco weather? Layers! A typical day might start foggy and cool, become sunny and warm by noon, and then turn windy and chilly by evening. Here are some must-haves:

A light but warm jacket (windproof or fleece is best)
A scarf or hoodie for added warmth
Comfortable walking shoes (hills and sudden rain showers make good footwear essential)
Sunglasses and sunscreen (when the sun is out, it can be intense!)

Final Thoughts

San Francisco’s weather may be unpredictable, but that’s part of its charm. Whether you’re admiring the fog rolling through the Golden Gate, enjoying a sunny afternoon in Dolores Park, or bundling up for a chilly evening stroll along Fisherman’s Wharf, the city’s climate is an integral part of its character. Embrace the layers, check the forecast often, and get ready to experience the ever-changing beauty of San Francisco’s unique weather!