San Francisco

Microclimates

Seven miles across, and the weather changes with the block. Here is why, from the ocean down to your street.

6.5 – 12.5
hours of summer fog a day
bayside → southwest
13°F
between our coolest and warmest month
most US cities: 40+
84%
of the year's rain falls Nov – Mar
July: none
2.5×
house price, Sun vs Persistent Fog
single-family, 2026

Climate

Köppen: Csb

Warm-summer Mediterranean

Temperate

Coldest month averages above 32°F (or 26.6°F).

Dry summer

Driest summer month under 1.6 in, and a third or less of the wettest winter month.

Warm summer

Every month averages under 71.6°F; at least four average above 50°F.

Does San Francisco qualify?

CColdest monthabove 32°F52°F (Jan)✓
sDriest summer monthunder 1.6 in0.0 in (Jul)✓
sWettest winter vs driest summer3× or more4.5 in vs none✓
bWarmest monthunder 71.6°F63°F (Sep)✓
bMonths above 50°F4 or more12 of 12✓
Monthly mean = average of the daily high and low. Summer is April–September.
  • Seville, 37.4°N97°F
  • Athens, 38.0°N92°F
  • Richmond VA, 37.5°N89°F
  • San Francisco, 37.8°N67°F
  • Dry-summer climates like ours cover about 2% of Earth's land — Porto, Valparaíso and the Oregon coast share our code.
  • One code covers the whole city. The sections below break it down.

Why It’s Cold

HNorth Pacific Highair sinks and warmsInversionthe lidMARINE LAYERPacific52–56°FupwellingGolden Gatesea-level gapCentral Valley95–105°Frising heat pullsthe coast inland
Schematic, west to east. Not to scale.

A cold current

The California Current runs south past us all year.

Upwelling

Northwest winds push surface water offshore; cold water rises to replace it. The ocean at Ocean Beach sits at 52–56°F in August.

The North Pacific High

Parked offshore from spring to fall. It blocks storms, and its sinking air lays a warm lid — the inversion — over the cool air below.

The Central Valley

95–105°F inland. Hot air rises, pressure falls, and marine air gets pulled through the gaps in the Coast Range.

  • The sea-level gaps are the Golden Gate, the San Bruno Gap, the Petaluma Gap and Carquinez. They act as nozzles.
  • Hotter Valley = harder push. The fog is strongest when inland California is at its worst.
  • Winter turns it off: the High slides south, storms arrive, the lid breaks up. The clearest days of the year follow a January storm.

The Year

Average high and low, °F

highlow

Rain, inches a month

106°FHottest day on recordSep 1, 2017
27°FColdest day on recordDec 11, 1932
1976Last measurable snow downtownFebruary 5
  • September is the warmest month, October second. June is not summer here.
  • Very little air conditioning in the housing stock, and not much heating either.
  • 72°F in the Mission and 58°F with a 25 mph wind at Ocean Beach, same hour, same day.
Month-by-month table
San Francisco Downtown · 1991-2020 normals
MonthHighLowRain
Jan57°46°4.4"
Feb61°48°4.4"
Mar62°49°3.2"
Apr63°50°1.5"
May64°52°0.6"
Jun67°53°0.2"
Jul67°55°—
Aug68°56°0.1"
Sep70°56°0.2"
Oct69°54°1.1"
Nov63°50°2.6"
Dec58°47°4.5"

Bay Micro

Around the Bay

The Bay Area’s eleven microclimates

Pacific OceanSan Francisco BaySan Pablo BayMt Tamalpais, 2,572 ftMt TamalpaisMt Diablo, 3,849 ftMt DiabloLoma Prieta, 3,786 ftLoma PrietaSan FranciscoOaklandSan JoseSanta RosaNapaPetalumaWalnut CreekLivermorePalo AltoHalf Moon BaySan Rafael1. The Fog Coast — July 63°F12. The City — July 67°F23. The Bayshore — July 76°F34. The Redwood Ridges — July 78°F45. The Hills — July 80°F56. The Wind Tunnel — July 81°F67. Tam's Shadow — July 82°F78. The Sun Bowl — July 84°F89. The Delta Breeze — July 86°F910. Wine Country — July 88°F1011. Over the Hills — July 91°F11
  1. 1
    The Fog Coast 63°FFirst land the marine layer touches. Grey summers, green winters.Bodega Bay · Point Reyes · Pacifica · Half Moon Bay
  2. 2
    The City 67°FAll four fog zones in seven miles — see below.San Francisco
  3. 3
    The Bayshore 76°FMarine air softened by the crossing. The region's mildest strip.Berkeley · Oakland · San Mateo · Burlingame
  4. 4
    The Redwood Ridges 78°FThe Santa Cruz Mountains crest. Fog-catching redwoods, up to 45 inches of rain.Skyline · Kings Mountain · La Honda
  5. 5
    The Hills 80°FOverlooking Berkeley and Oakland, above much of the marine layer. Warmer, more sun, less fog.Berkeley & Oakland hills · 500–800 ft
  6. 6
    The Wind Tunnel 81°FA low break in the Coast Range. One of the windiest corridors in California.Petaluma · Sears Point
  7. 7
    Tam's Shadow 82°FMount Tamalpais blocks the direct marine push.San Rafael · Mill Valley · Novato
  8. 8
    The Sun Bowl 84°FFar from every gap and in the mountains' rain shadow. Driest and sunniest.Redwood City · Palo Alto · San Jose · Los Gatos
  9. 9
    The Delta Breeze 86°FWhere the Bay narrows into the Delta. Hot afternoons, then an evening breeze through the Carquinez Strait cools the whole inland valley.Benicia · Martinez · Pittsburg · Antioch
  10. 10
    Wine Country 88°FHot afternoons, fog-cooled nights — the swing that grows the grapes.Santa Rosa · Sonoma · Napa · CalistogaWine AVA map →
  11. 11
    Over the Hills 91°FEast of the Berkeley–Oakland hills: 90°F+ afternoons, cooled at night by the Delta breeze.Walnut Creek · Concord · Livermore · Fairfield
Typical July afternoon high. Zones blend into each other on purpose — real edges follow ridgelines and move day to day.
  • Sonoma CoastBodega Bay57°62°30″
  • Outer Marin coastPoint Reyes56°63°32″
  • CoastsidePacifica, Half Moon Bay59°64°27″
  • San Francisco — westOuter Sunset57°64°22″
  • San Francisco — eastMission, North Beach58°72°22″
  • East Bay flatsBerkeley, Oakland58°73°24″
  • Santa Cruz Mtns crestSkyline52°78°45″
  • Mid-PeninsulaSan Mateo, Palo Alto59°79°18″
  • Petaluma GapPetaluma57°82°25″
  • Central MarinSan Rafael57°82°32″
  • South BaySan Jose59°84°15″
  • Sonoma ValleySanta Rosa57°87°32″
  • Upper Napa ValleyCalistoga57°90°36″
  • Inland East BayWalnut Creek, Livermore56°90°16″
Rounded typical values, shown for the spread rather than to be quoted for any one town.
  • 28°F separates Bodega Bay from Livermore on the same July afternoon, 80 miles apart.
  • Skyline collects three times the rain San Jose does — storms are forced up and over the Santa Cruz Mountains.
  • December afternoons barely vary — 52°F on Skyline to 59°F in San Jose. July is what sorts this region.

SF Micro

San Francisco Primary Microclimates

Fog

San Francisco split into its fog zones, one dot per home sold this yearOpen the Summer Fog Map →
SunTransitionFogPersistent Foghome sold this year
FogTerrainHazardsSun & wind

A July day on the west side

clearsolid
Schematic of the daily pattern, not an hourly measurement.

What it is

  • Air cooled to its dew point — the water it can no longer hold condenses.
  • Ours is advection fog: humid ocean air crossing water colder than itself.
  • Not tule fog — that forms on cold, still winter nights in the Central Valley.

Why summer

  • Every driver peaks May to August: strongest High, coldest water, hottest Valley.
  • Foggiest month: July.
  • September and October relax the pattern — our warmest, clearest months.

How deep the fog is

Shallow under 800 ftPeaks in sun above the fog
Typical 800 – 1,500 ftBurns off late morning
Deep over 2,000 ftGrey all day
The hill is 922 ft, the height of Twin Peaks. Gold line: the inversion capping the layer.

The ridge

  • Marine air comes in low and heavy and stacks against the western slope.
  • It spills through the saddles and around the ends rather than over the top.
  • Cole Valley sits below a saddle and gets the overflow. The Castro, a mile east, stays in the sun.

Two doors

  • The Golden Gate feeds the northern half — Presidio, Richmond, Marina, across the Bay.
  • The San Bruno Gap feeds the south along the 280 corridor.
  • That second door is why Ingleside and Lakeshore see far more fog than the Mission a few miles north.

Inversion

  • A strong cap stops the deck mixing out — it can sit all day.
  • A weak cap lets the morning sun break it up.
  • Offshore wind removes it: the fog goes out to sea and the city gets its 80°F days.

The Ridge

The ridge down the middle of the city — Mount Davidson 928 ft, Twin Peaks 922, Mount Sutro 909 — does to marine air what the Coast Range does to the region.

top of the marine layerclearFOGTwin Peaks 922 ft12.5hLakeshore9hSunset9hCole Valley8.5hNoe Valley7.5hMission6.5hNorth Beach
Schematic. Hours are each neighborhood’s measured summer fog average.

Sun

8 or lessfog hrs / day
37neighborhoods
  • The northeast quadrant, in the lee of the ridge.
  • Eight to ten degrees warmer than the west side on a summer afternoon.
  • Least wind, most reliable sun, highest price per foot.

North Beach, Russian Hill, Nob Hill, Telegraph Hill, Marina, Hayes Valley, Mission Dolores, South of Market

Transition

8.5fog hrs / day
22neighborhoods
  • The 8.5-hour line, where fog spills through the ridge's saddles — 22 neighborhoods reach it.
  • Fog arrives in the late afternoon, gone by eleven the next morning.
  • Sun on one block, grey on the next — 30 neighborhoods cover more than one zone.

Noe Valley, Eureka Valley, Lower Pacific Heights, Laurel Heights / Jordan Park, Bernal Heights, Potrero Hill, Haight Ashbury, Presidio Heights

Fog

9 – 11fog hrs / day
41neighborhoods
  • West of the ridge, plus the southern tier fed by the San Bruno Gap.
  • Summer afternoons in the low 60s with a 20+ mph west wind.
  • Grey mornings and evenings, with a clear spell around midday.

Inner Richmond, Outer Richmond, Inner Sunset, Outer Sunset, Cole Valley, Glen Park, West Portal, Excelsior

Persistent Fog

over 11fog hrs / day
17neighborhoods
  • The southwest corner — Ingleside, Oceanview, Parkmerced, Lakeshore.
  • Runs to 12.5 hours a day, the most in the city.
  • The city's most affordable houses.

St. Francis Wood, Westwood Park, Ingleside Terraces, Balboa Terrace, Merced Heights, Sunnyside, Outer Mission

  • Treasure Island6h
  • North Beach6.5h
  • Mission7.5h
  • Potrero Hill8h
  • Noe Valley8.5h
  • Outer Sunset9h
  • Glen Park10h
  • Parkside10.5h
  • West Portal11h
  • Lakeshore12.5h
Average summer fog and low-cloud hours per day — USGS analysis of GOES satellite imagery, 1999–2009. The same data the fog map is drawn from.

Single-family median, 2026

$4.20MSun · 237 sales$1,639/sq ft
$3.20MTransition · 135 sales$1,535/sq ft
$1.87MFog · 1,094 sales$1,132/sq ft
$1.70MPersistent Fog · 268 sales$998/sq ft

Houses only, each counted by the fog zone at the house. Across all property types the order flips, because the Sun zone is mostly condos.

Block by Block

Wind

  • 20–30 mph through the Golden Gate from midafternoon into the night.
  • Ridgelines speed it up; the ground just downwind of a hill can be 10°F warmer and half as windy.
  • Downtown towers throw their own gusts — a plaza can be unusable while the street behind it is calm.

Sun angle

  • Low winter sun makes the direction a slope faces decisive.
  • A north-facing slope can sit in its own shadow for weeks.
  • A rear yard north of a three-story building may get no direct winter sun at all.

Elevation

  • The fog deck has a top, usually 800–1,500 ft.
  • Twin Peaks in sun above a white sea, Cole Valley 300 ft below it in grey — same afternoon.
  • Higher is not automatically better: on a deep day the hilltops are first in and last out.

Grade

  • Cold air is dense — at night it drains downhill and pools in the low ground.
  • Glen Canyon and the Sunset's interior hollows run colder overnight than the slopes above them.
  • A steep south-facing lot collects far more winter sun than flat ground next door.

Sun on the Lot

Dec 21 · 29°Jun 21 · 76°JuneDecember
Noon sun at 37.8°N. Same house, six months apart.

The lot from above

June 21December 21Yard north of the house
streetyardhouseN13h 41m of sun on the yard
streetyardhouseN1h 10m of sun on the yard
Yard south of the house
streetyardhouseN12h 58m of sun on the yard
streetyardhouseN7h 54m of sun on the yard
Sun on the yard:0 h14 h the house neighbors
The winter sun stays low in the southern sky, so a yard north of its house sits in the house’s shadow — and a yard south of it doesn’t. 25 × 100 ft lot, 30 ft row houses, flat ground.
  • In June the sun rises and sets behind the north wall — northeast and northwest.
  • In December it rises and sets well south of east and west, and tops out at 29°.
  • A north-facing rear yard spends most of the winter in its own house's shadow.

A 40 ft neighbor to the south, at noon

SOUTHNORTHNeighbor40 ftYour house50 ft between wallsDec noon · 29°lowest 13 ft ofyour wall in shadowJun noon · 76°shadow ends 10 ft out
At noon a shadow is 1.8× the height of what casts it in December, and 0.26× in June.

December noon sun on a 20% grade

SNSouth-facing slopeSun meets ground at 40°+34% winter sun
SNFlat groundSun meets ground at 29°baseline
SNNorth-facing slopeSun meets ground at 17°−38% winter sun
Energy per square foot of ground scales with the sine of the angle the sun meets it at.

Measure it yourself

clearblocksyousouthThe half ruleAnything due south taller than half its distance from you blocks December noon sun.A tree 40 ft away has to stay under 22 ft.
123yousouthThe fist ruleA fist at arm’s length covers about 10°. December noon sun sits three fists up.If a roofline due south is above three fists, you lose winter noon sun.
  • Sun Seeker or Sun Surveyor (phone): draws the sun's path over the camera view.
  • Compass and inclinometer apps: the direction and angle to any roofline or tree.
  • Google Earth: 3D buildings and a sun slider for any date.
  • A photo from the yard at noon near December 21 settles it.

Sky chart — the whole sky, seen from the rear yard

30°60°NESWbuildingtreehilloverhead
June 2112h 45m direct sun of 14h 37m daylight
Mar / Sep 2110h 18m direct sun of 12h 00m daylight
December 214h 41m direct sun of 9h 23m daylight

Grey is the skyline: whatever the sun passes behind is lost sun. Dots mark 9am, noon and 3pm. An example lot — a phone sun app draws this for a real one.

On the mapThe sun layers show which slopes collect more or less sun than flat ground — summer, winter and equinox.
Sun & wind zonesOpen the map

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Climate normals: NOAA/NWS, downtown San Francisco station. Fog hours: USGS analysis of GOES satellite imagery, 1999–2009. Regional figures are rounded. Diagrams are schematic. Any single year departs from all of it.