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Beyond the Forecast

March 18 in Los Angeles

Weather forecasts run out after about two weeks. For any date further out than that, the honest answer isn't a single number — it's the range Los Angeles actually delivers on this date, and how often.

On March 18, Los Angeles, CA typically reaches 71°F, but has run anywhere from 63°F to 83°F in eight years out of ten. About 84% of March 18s see no measurable precipitation.

Daytime high71°F
63°F8 years in 10 land in here83°F
Overnight low54°F
47°F8 years in 10 land in here59°F

The odds on March 18

84%
Dry day
No measurable precipitation
3%
90°F or hotter
Daytime high

Odds computed from the last 30 years (19972026).

This date is moving

Highs around March 18 have warmed about 0.4°F per decade since 1970 — roughly 2.4°F across the record. The figures above are shifted along that trend to 2026, so they describe today's climate rather than the average of the last 56 years.

Where this comes from: 855 daily observations from LOS ANGELES DOWNTOWN/USC, covering 19702026. We pool every day within 7 days of March 18 — a single calendar date has only about 56 readings, far too few to place a 10th percentile you'd want to trust.

Why it's not a plain average: A climatology computed straight across 19702026 describes the middle of that period, not today, so as a statement about the present it runs cold. We fit a trend on year and shift each observation to 2026 before taking the range. The probabilities use the last 30 years instead — shifting a temperature along a trend is well defined, shifting “did it rain” is not.

What this is not: Not a forecast. It is what Los Angeles, CA has actually done on this date, which is the only defensible answer once you're past the two-week horizon where real forecasts stop. Data: NOAA NCEI GHCN-Daily.

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