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CheckWeather USDiamond Bar
Forecast confidence: Medium · models disagree by 6°F

Diamond Bar weather

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Mostly clear,rain likely tomorrow

NWS, the American and the European model put Diamond Bar's high today between 88° and 93°, a 6° split. Tomorrow looks heavy drizzle around 79°, with a 98% chance of rain.

91°61°
79°70°
92°69°
93°73°
99°76°
98°76°
Todaysplit ±6°Tomorrowsplit ±7°Mondaysplit ±9°Tuesdaysplit ±7°Wednesdaysplit ±7°Thursdaysplit ±7°
NWSNational Blend (NBM)
88°
Mostly clear
Today 88°·Low 63°·Rain 0%
AmericanNOAA GFS
93°
Mostly clear
Today 93°·Low 59°·Rain 0%
EuropeanECMWF
93°
Light drizzle
Today 93°·Low 61°·Rain 65%

The weather map: all three models at once

NWS, American, European side by side around Diamond Bar and nearby towns.Live rain radar →
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Next 14 hours

consensus of the three models

14-day forecast

where the models agree, and where they split
Today
Mostly clear
91° 61°
±6°
Tomorrow
Heavy drizzle
79° 70°
±7°
Mon
Cloudy
92° 69°
±9°
Tue
Cloudy
93° 73°
±7°
Wed
Cloudy
99° 76°
±7°
Thu
Clear
98° 76°
±7°
Fri
Clear
91° 73°
models agree
Sat
Clear
86° 69°
models agree
Sun
Clear
88° 67°
±8°
Mon
Clear
90° 67°
±5°
Tue
Light drizzle
92° 69°
±13°
Wed
Cloudy
94° 73°
models agree
Thu
Light drizzle
90° 71°
±8°
Fri
Clear
90° 71°
±11°

Diamond Bar, CA is at its warmest in Jul (average highs near 94°F) and coldest in Feb (lows around 44°F), with roughly 31 in of precipitation across the year. Below, compare what NWS, American, European forecast for Diamond Bar 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.

Diamond Bar climate by month

average daytime high and overnight low across a typical year
Jan
60°
45°
Feb
61°
44°
Mar
62°
46°
Apr
72°
49°
May
75°
53°
Jun
82°
57°
Jul
94°
63°
Aug
93°
64°
Sep
87°
62°
Oct
84°
58°
Nov
73°
50°
Dec
68°
48°

Which forecast is most accurate in Diamond Bar?

CheckWeather Score — graded against the weather that actually happened
ProviderCheckWeather Score🌡 Temp💨 Wind🌧 RainRun by
European logo
European ★ Best
94
/100rank #1
87±1.3°F96±1.2 mph100100% hitECMWF - European Centre for Medium-Range Weather ForecastsReading, United Kingdom
American logo
American
92
/100rank #2
84±1.6°F93±2.1 mph100100% 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.

Where the models disagree

temperature and rain, judged separately
DayTemperatureRain
Today±6°88° to 93°±65%0% to 65% chance
Tomorrow±7°75° to 82°±54%44% to 98% chance
Mon±9°88° to 97°±15%3% to 18% chance
Tue±7°90° to 97°±2%8% to 10% chance
Wed±7°95° to 102°±6%9% to 15% 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 Diamond Bar

today, local time
Sunrise
06:27
Sunset
19:11
Daylight
12h 44m

Common questions

What's the weather in Diamond Bar today?
On this page we show what NWS, American, European each forecast for Diamond Bar 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 Diamond Bar today or tomorrow?
Check the hourly strip and 7-day forecast above. We compare rain from NWS, American, European for Diamond Bar 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 Diamond Bar?
Over the last 30 days, the European model has been the most accurate for Diamond Bar (CheckWeather Score 94/100), ahead of the American at 92. We grade every model against the recorded weather. See the US accuracy scoreboard for the full method.
What is the warmest month in Diamond Bar?
July is typically the warmest month in Diamond Bar, with average highs around 94°F.
How cold does Diamond Bar get?
The coldest month in Diamond Bar is February, when overnight lows average about 44°F.
How much rain does Diamond Bar get?
Diamond Bar sees roughly 31 in of precipitation a year, with February usually the wettest month.

Nearby

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