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Forecast confidence: Low · models disagree by 12°F

Fullerton weather

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Mostly clear,rain likely tomorrow

NWS, the American and the European model put Fullerton's high today between 82° and 93°, a 12° split. Tomorrow looks drizzle around 80°, with a 92% chance of rain, and the models disagree, so treat it as uncertain.

87°64°
80°70°
90°70°
91°73°
95°76°
91°76°
Todaysplit ±12°Tomorrowsplit ±10°Mondaysplit ±14°Tuesdaysplit ±13°Wednesdaysplit ±11°Thursdaysplit ±13°
NWSNational Blend (NBM)
87°
Mostly clear
Today 87°·Low 65°·Rain 1%
AmericanNOAA GFS
93°
Cloudy
Today 93°·Low 62°·Rain 1%
EuropeanECMWF
82°
Clear
Today 82°·Low 65°·Rain 31%

The weather map: all three models at once

NWS, American, European side by side around Fullerton and nearby towns.Live rain radar →
Loading the three model maps…

Next 14 hours

consensus of the three models

14-day forecast

where the models agree, and where they split
Today
Mostly clear
87° 64°
±12°
Tomorrow
Drizzle
80° 70°
±10°
Mon
Mostly clear
90° 70°
±14°
Tue
Cloudy
91° 73°
±13°
Wed
Mostly clear
95° 76°
±11°
Thu
Mostly clear
91° 76°
±13°
Fri
Mostly clear
86° 73°
±8°
Sat
Mostly clear
82° 70°
±7°
Sun
Mostly clear
83° 69°
models agree
Mon
Clear
84° 69°
±12°
Tue
Light drizzle
86° 69°
±20°
Wed
Light drizzle
86° 73°
±15°
Thu
Light drizzle
83° 71°
models agree
Fri
Clear
84° 71°
models agree

Fullerton, 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 Score🌡 Temp💨 Wind🌧 RainRun by
American logo
American ★ Best
87
/100rank #1
74±2.6°F91±2.7 mph100100% hitNOAA / NCEP (United States)College Park, Maryland, USA
European logo
European
62
/100rank #2
8±9.2°F95±1.6 mph100100% 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.

Where the models disagree

temperature and rain, judged separately
DayTemperatureRain
Today±12°82° to 93°±30%1% to 31% chance
Tomorrow±10°75° to 85°±52%40% to 92% chance
Mon±14°84° to 98°±15%4% to 19% chance
Tue±13°85° to 98°±4%6% to 10% chance
Wed±11°90° to 101°±4%10% to 14% 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
06:28
Sunset
19:12
Daylight
12h 44m

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 87/100), 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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