June is the foggiest month of the year in San Francisco. While the rest of the country celebrates the start of summer with warm, sunny weather, San Francisco disappears under a thick marine layer that can keep western neighborhoods in the mid-50s for days at a time. Average highs in June are 66 degrees F, but that number masks enormous variation across the city: the Mission District might hit 72 degrees in afternoon sunshine while the Outer Sunsetsits at 55 degrees under a gray ceiling less than three miles away. June is the month when San Francisco's microclimate personality is on full display.
Why Is June the Foggiest Month?
The fog machine runs hardest in June because the temperature contrast between the Pacific Ocean and the Central Valley reaches its peak. The California Current keeps ocean surface temperatures at 52-55 degrees F, while the Central Valley heats to 95-105 degrees on most June afternoons. That 40 to 50 degree temperature difference creates a powerful pressure gradient that pulls cold, moist marine air through the Golden Gate with force. The cold air condenses as it crosses the coast, forming the marine layer that blankets the western half of the city.
June fog follows a daily rhythm. It is thickest in the evening and early morning, when the land has cooled and the pressure gradient relaxes. By mid-morning, solar heating begins thinning the fog from above, and by early afternoon, the eastern neighborhoods and downtown typically clear while the coast stays socked in. This burn-off pattern creates the classic San Francisco June experience: foggy mornings that give way to partly cloudy afternoons, with the fog pushing back in by dinnertime.
June Temperatures by Neighborhood
The temperature spread across San Francisco in June is dramatic. The Outer Sunset and the Richmond, which face the ocean and sit directly in the path of marine flow through the Golden Gate, average highs of about 60 degrees F in June. The Mission District, which is sheltered from the fog by Twin Peaks and the surrounding hills, averages about 70 degrees. The Embarcadero and downtown fall somewhere in between at 64-67 degrees, depending on whether the afternoon fog reaches the bay side of the city.
This east-west temperature gradient is the reason experienced San Franciscans dress in layers every day, even in June. You can walk from a sunny 72-degree lunch in the Mission to a foggy 56-degree scene at Ocean Beach in 20 minutes. The temperature does not change gradually. It drops as you cross the hill line that separates the sun-exposed eastern slopes from the fog-facing western slopes.
Rain and Wind in June
Rain is almost nonexistent in June. Average rainfall is a trace, essentially zero. San Francisco's wet season ended months ago, and the dry season is firmly established. The moisture you feel in June is not rain but fog drip, the condensation that forms on surfaces as the marine layer pushes through. Walk under cypress trees in Lands End during a foggy afternoon and you will get dripped on without a cloud in the sky above the fog deck.
Wind is the other signature feature of June. Afternoon winds through the Golden Gate regularly hit 20-30 mph, driven by the same pressure gradient that produces the fog. The windiest spots are the beaches, the headlands, and the west-facing neighborhoods. Ocean Beach in June is not a sunbathing destination. It is a wind tunnel. The Crissy Field area is popular with windsurfers and kiteboarders precisely because June winds are strong and reliable.
What to Pack for June in San Francisco
June in San Francisco requires layers. A warm mid-layer (fleece or light sweater), a wind-resistant outer layer, and long pants are essential for the western half of the city and any time you will be outdoors near the water. If you are spending the day in the Mission District or downtown, you can get away with lighter clothing, but bring the layers in your bag because the fog can arrive quickly as the afternoon progresses.
The biggest mistake visitors make in June is assuming San Francisco summer weather is anything like the rest of California. Los Angeles is 85 degrees and sunny. Sacramento is 95 degrees. San Francisco is 58 degrees and foggy. Mark Twain almost certainly did not say "the coldest winter I ever spent was a summer in San Francisco," but the sentiment is accurate for June, and especially for first-time visitors expecting beach weather.