Golden State WeatherRegionsTransverse Ranges

Transverse Ranges

The only major east-west ranges on the West Coast, and the reason Southern California's weather is strange.

Sundowner windsExtreme south-slope rainfall ratesSanta Ana canyon jets

The San Gabriels, San Bernardinos, Santa Ynez and Santa Monicas run across the grain of the continent, and almost everything distinctive about Southern California weather follows from it. They wall the coastal basins off from the desert, so a marine layer can sit against them for months. They rise fast enough — sea level to 10,000 feet in 20 miles — to squeeze extraordinary rainfall out of a south-facing storm. And when the pressure gradient reverses, their canyons become the nozzles that make Santa Ana and Sundowner winds.

Elevation range: 500 ft → 11,503 ftHigh point: San Gorgonio Mountain
Relief: 11,003 ftTop to bottom, inside this region
Span: 228 × 62 miEast–west by north–south
Annual rainfall: 15–45″Driest to wettest ground here
Köppen types: CsaCsbDsb5 counties

Open climate division

Map of Transverse Ranges within California.

Where it is. The highlighted frame is this region's viewport; the others are its neighbours.

The four seasons here

NOT A GENERIC SEASON WITH THE PLACE NAME SWAPPED IN

Winter

The wet season, and where a warm storm parks against a south slope it produces the state's highest rain rates.

Spring

Snow lingers on San Gorgonio and Baldy into May while the coast below is in the sixties.

Summer

Dry, with monsoon thunderstorms over the eastern peaks from July.

Autumn

Sundowners in Santa Barbara, Santa Anas everywhere east — the most dangerous fire weather in California.

Places in this region

3 PLACES, LOWEST FIRST

NOAA/NCEI 1991–2020 monthly normals, from the nearest publishing station at a comparable elevation. Full twelve-month tables are on each place's own page.
Place	Elevation	Jan high	Jan low	Jul high	Jul low	Annual precip	Snow
Ojai	745	66°	34°	89°	54°	20.7″	—
Mount Wilson	5,710	56°	38°	84°	64°	32.2″	—
Big Bear Lake	6,752	46°	24°	80°	50°	20.0″	59″

Terrain and gradients

WHAT THE ELEVATION ACTUALLY DOES

-0.5°FJuly lapse rate per 1,000 ft

-2.0°FJanuary lapse rate per 1,000 ft

+0.6″Rainfall per 1,000 ft

1.0×Highest ÷ lowest station precipitation

Ranges and passes

A PASS IS A WIND FEATURE FIRST

Transverse RangesRuns across the grain of the coast. The wall that makes the LA Basin a basin.RANGECajon PassThe main Santa Ana conduit into the Inland Empire, and the notch the San Andreas uses too.PASS

Who forecasts it

OFFICIAL FORECASTS AND WARNINGS COME FROM HERE

NWS Los AngelesSouth coast, Transverse Ranges, western MojaveNWS LOXWEATHER.GOV NWS San DiegoSan Diego, the Inland Empire and the low desertNWS SGXWEATHER.GOV NWS HanfordSan Joaquin Valley and the southern SierraNWS HNXWEATHER.GOV

Golden State Weather is not a source of watches or warnings. For those, go to the offices above.

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