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Forecast confidence: Medium · models disagree by 5°F

Fullerton weather

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Mostly clear,much the same tomorrow

NWS, the American and the European model put Fullerton's high today between 75° and 80°, a 5° split. Tomorrow looks cloudy around 80°, with a 0% chance of rain.

78°65°
80°63°
80°66°
77°67°
79°66°
83°67°
Todaysplit ±5°Tomorrowsplit ±6°Sundaysplit ±9°Mondaysplit ±5°Tuesdaysplit ±6°Wednesdaysplit ±5°
NWSNational Blend (NBM)
79°
Mostly clear
Today 79°·Low 65°·Rain 0%
AmericanNOAA GFS
80°
Cloudy
Today 80°·Low 64°·Rain 0%
EuropeanECMWF
75°
Partly cloudy
Today 75°·Low 66°·Rain 0%
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Fullerton weather alerts and warnings

active National Weather Service watches, warnings and advisories

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Fullerton weather in numbers

from 30 years of measured normals

Fullerton swings 40°F across the year, from 86°F highs in July to 46°F lows in January, and February is usually the wettest month in a year that brings about 27 in of precipitation.

Warmest month
July
86°F average high
Coldest month
January
46°F average low
Wettest month
February
27 in a year
Below freezing
Never
overnight lows stay above 32°F
Comfortable
4 months
January, March, April and May
Residents
141,000
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The weather map: all three models at once

NWS, American, European side by side around Fullerton and nearby towns.Live rain radar →
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Fullerton 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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Fullerton 10-day forecast, out to 14 days

where the models agree, and where they split
Today
Mostly clear
78° 65°
±5°
Tomorrow
Cloudy
80° 63°
±6°
Sun
Cloudy
80° 66°
±9°
Mon
Partly cloudy
77° 67°
±5°
Tue
Partly cloudy
79° 66°
±6°
Wed
Mostly clear
83° 67°
±5°
Thu
Mostly clear
84° 68°
±11°
Fri
Mostly clear
85° 70°
±18°
Sat
Partly cloudy
87° 71°
±22°
Sun
Cloudy
91° 73°
±18°
Mon
Mostly clear
89° 74°
±17°
Tue
Cloudy
88° 76°
±11°
Wed
Clear
80° 70°
±5°
Thu
Clear
77° 68°
models agree

Fullerton, California (CA) is at its warmest in Jul (average highs near 86°F) and coldest in Jan (lows around 46°F), with roughly 27 in of precipitation across the year. Below, compare what NWS, American, European forecast for Fullerton 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.

Fullerton climate by month

average daytime high and overnight low across a typical year
Jan
63°
46°
Feb
63°
46°
Mar
63°
48°
Apr
71°
51°
May
71°
54°
Jun
77°
59°
Jul
86°
63°
Aug
86°
64°
Sep
83°
63°
Oct
82°
58°
Nov
74°
53°
Dec
69°
51°

Which forecast is most accurate in Fullerton?

CheckWeather Score, graded against the weather that actually happened
ProviderCheckWeather-scoreTempWindRainRun by
American logo
American ★ Best
82
/100rank #1
77±2.3°F91±2.8 mph8290% hitNOAA / NCEP (United States)College Park, Maryland, USA
European logo
European
62
/100rank #2
13±8.7°F95±1.4 mph9597% hitECMWF - European Centre for Medium-Range Weather ForecastsReading, United Kingdom

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±5°75° to 80°models agree0% to 0% chance
Tomorrow±6°77° to 82°models agree0% to 0% chance
Sun±9°76° to 85°±4%0% to 4% chance
Mon±5°75° to 80°±2%1% to 3% chance
Tue±6°76° to 82°±2%0% to 2% 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 Fullerton

today, local time
Sunrise
06:37
Sunset
18:53
Daylight
12h 16m

Common questions

What's the weather in Fullerton today?
On this page we show what NWS, American, European each forecast for Fullerton 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 Fullerton today or tomorrow?
Check the hourly strip and 7-day forecast above. We compare rain from NWS, American, European for Fullerton 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 Fullerton?
Over the last 30 days, the American model has been the most accurate for Fullerton (CheckWeather Score 82/100), ahead of the European at 62. We grade every model against the recorded weather. See the US accuracy scoreboard for the full method.
What is the warmest month in Fullerton?
July is typically the warmest month in Fullerton, with average highs around 86°F.
How cold does Fullerton get?
The coldest month in Fullerton is January, when overnight lows average about 46°F.
How much rain does Fullerton get?
Fullerton sees roughly 27 in of precipitation a year, with February usually the wettest month.

Nearby

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