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Forecast confidence: High · models disagree by 1°F

Altadena weather

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Mostly clear,much the same tomorrow

NWS, the American and the European model agree on a high near 79° in Altadena today. Tomorrow looks cloudy around 83°, with a 0% chance of rain.

79°59°
83°60°
81°62°
77°62°
81°62°
87°68°
Todaymodels agreeTomorrowmodels agreeSundaymodels agreeMondaymodels agreeTuesdaymodels agreeWednesdaysplit ±9°
NWSNational Blend (NBM)
79°
Mostly clear
Today 79°·Low 60°·Rain 1%
AmericanNOAA GFS
79°
Partly cloudy
Today 79°·Low 58°·Rain 1%
EuropeanECMWF
79°
Clear
Today 79°·Low 60°·Rain 0%
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Altadena weather alerts and warnings

active National Weather Service watches, warnings and advisories

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Altadena weather in numbers

from 30 years of measured normals

Altadena swings 48°F across the year, from 91°F highs in July to 43°F lows in February, and February is usually the wettest month in a year that brings about 36 in of precipitation.

Warmest month
July
91°F average high
Coldest month
February
43°F average low
Wettest month
February
36 in a year
Below freezing
Never
overnight lows stay above 32°F
Comfortable
4 months
April, May, June and November
Residents
43,000
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The weather map: all three models at once

NWS, American, European side by side around Altadena and nearby towns.Live rain radar →
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Altadena hourly forecast: next 14 hours

consensus of the three models

Rain in the next 24 hours, model by model

each model's own hourly precipitation, side by side

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Altadena 10-day forecast, out to 14 days

where the models agree, and where they split
Today
Mostly clear
79° 59°
models agree
Tomorrow
Cloudy
83° 60°
models agree
Sun
Partly cloudy
81° 62°
models agree
Mon
Partly cloudy
77° 62°
models agree
Tue
Mostly clear
81° 62°
models agree
Wed
Clear
87° 68°
±9°
Thu
Clear
87° 69°
±5°
Fri
Cloudy
86° 69°
±8°
Sat
Mostly clear
86° 68°
±16°
Sun
Cloudy
90° 72°
±18°
Mon
Mostly clear
90° 74°
±17°
Tue
Cloudy
92° 79°
models agree
Wed
Clear
85° 69°
±6°
Thu
Clear
79° 66°
±9°

Altadena, California (CA) is at its warmest in Jul (average highs near 91°F) and coldest in Feb (lows around 43°F), with roughly 36 in of precipitation across the year. Below, compare what NWS, American, European forecast for Altadena right now, and see exactly where they disagree.

We grade every model against the weather that actually happened, so you can see which forecast model is most accurate in United States before you trust any single number.

Altadena climate by month

average daytime high and overnight low across a typical year
Jan
59°
44°
Feb
58°
43°
Mar
59°
44°
Apr
68°
48°
May
70°
52°
Jun
77°
58°
Jul
91°
69°
Aug
88°
68°
Sep
83°
64°
Oct
80°
61°
Nov
69°
51°
Dec
66°
50°

Which forecast is most accurate in Altadena?

CheckWeather Score, graded against the weather that actually happened
ProviderCheckWeather-scoreTempWindRainRun by
European logo
European ★ Best
95
/100rank #1
90±1.0°F97±1.0 mph100100% hitECMWF - European Centre for Medium-Range Weather ForecastsReading, United Kingdom
American logo
American
90
/100rank #2
88±1.2°F96±1.3 mph8994% hitNOAA / NCEP (United States)College Park, Maryland, USA

The CheckWeather Score blends temperature, wind and rain accuracy, each measured against ERA5 (the recorded weather) over the last 30 days across 1999 cities. Lower error means a higher score. See which forecast model is most accurate in United States, how we measure forecast accuracy, or which model each weather app uses.

What do you think of the forecasts?

your vote counts

The accuracy above is the measured record. This is your opinion: which forecast service do you trust most in United States? Give each 1 to 5 stars.

NWSNational Blend (NBM)
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AmericanNOAA GFS
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EuropeanECMWF
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One vote per service. Anonymous: we store no personal data, only a one-way hash of your connection for a day to stop double votes.

Where the models disagree

temperature and rain, judged separately
DayTemperatureRain
Today±1°79° to 79°±1%0% to 1% chance
Tomorrow±2°82° to 85°models agree0% to 0% chance
Sun±4°79° to 83°models agree0% to 0% chance
Mon±4°75° to 79°±1%0% to 1% chance
Tue±4°79° to 83°±1%0% to 1% chance

The models often agree on temperature and still split on rain, and rain is usually what decides whether a plan survives. A wide rain range means the shower is genuinely uncertain, not that the forecast is wrong.

Sunrise and sunset in Altadena

today, local time
Sunrise
06:37
Sunset
18:54
Daylight
12h 17m

Common questions

What's the weather in Altadena today?
On this page we show what NWS, American, European each forecast for Altadena today, side by side and updated live. When all three agree the forecast is reliable; when they split, we flag it so you know the day is genuinely less certain.
Will it rain in Altadena today or tomorrow?
Check the hourly strip and 7-day forecast above. We compare rain from NWS, American, European for Altadena and flag the days where the models disagree on whether showers actually arrive, which is exactly when a single app can catch you out.
Which forecast is most accurate for Altadena?
Over the last 30 days, the European model has been the most accurate for Altadena (CheckWeather Score 95/100), ahead of the American at 90. We grade every model against the recorded weather. See the US accuracy scoreboard for the full method.
What is the warmest month in Altadena?
July is typically the warmest month in Altadena, with average highs around 91°F.
How cold does Altadena get?
The coldest month in Altadena is February, when overnight lows average about 43°F.
How much rain does Altadena get?
Altadena sees roughly 36 in of precipitation a year, with February usually the wettest month.

Nearby

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