Weather Tomorrow

Weather Tomorrow in Rancho Cucamonga, CA

Extreme Heat WarningUntil Sep 9, 5:30 AM

Extreme Heat Warning issued September 8 at 1:52PM PDT until September 9 at 8:00PM PDT by NWS San Diego CA

Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors. Do not leave young children and pets in unattended vehicles. Car interiors will reach lethal temperatures in a matter of minutes.

Heat AdvisoryUntil Sep 9, 5:30 AM

Heat Advisory issued September 8 at 1:52PM PDT until September 10 at 8:00PM PDT by NWS San Diego CA

Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors. Do not leave young children and pets in unattended vehicles. Car interiors will reach lethal temperatures in a matter of minutes.

Wednesday, September 9, 2026

100°Low 76°FColdHot
Clear

Precip chance

12%

Wind

0-10 mph

Humidity

56%

Feels like

98–78°F

Data source: National Weather Service (NOAA) · Updated just now

Tomorrow by Hour

76°Temperature trend100°
TimeTempConditionRain %Wind
7 AM☽80°FPartly Cloudy
2%
0 mph
8 AM☽80°FPartly Cloudy
2%
0 mph
9 AM☽78°FMostly Clear
2%
5 mph NE
10 AM☽78°FMostly Clear
2%
5 mph NE
11 AM☽78°FMostly Clear
2%
0 mph
12 PM☽77°FMostly Clear
2%
0 mph
1 PM77°FSunny
2%
0 mph
2 PM76°FSunny
2%
0 mph
3 PM79°FSunny
2%
0 mph
4 PM84°FSunny
2%
0 mph
5 PM88°FSunny
2%
0 mph
6 PM92°FSunny
11%
5 mph SW
7 PM96°FSunny
11%
5 mph SW
8 PM98°FSunny
11%
5 mph SW
9 PM99°FSunny
11%
10 mph SW
10 PM100°FSunny
11%
10 mph SW
11 PM99°FSunny
11%
10 mph W
12 AM98°FSunny
12%
5 mph SW
1 AM☽97°FMostly Clear
12%
10 mph W
2 AM☽92°FMostly Clear
12%
10 mph W
3 AM☽88°FMostly Clear
12%
5 mph SW
4 AM☽86°FMostly Clear
12%
0 mph
5 AM☽84°FMostly Clear
12%
0 mph
6 AM☽83°FPartly Cloudy
0%
0 mph

Precipitation Timeline

100%
50%
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<20%20-50%50-70%>70%

What to Wear Tomorrow

Extreme heat — stay cool and protected

Clothing

  • • Lightest possible clothing
  • • Wide-brim hat
  • • UV-protective shirt if outdoors

Footwear

Breathable sandals

Accessories

  • • Sunglasses
  • • Sunscreen

Conditions

High: 100°F

Low: 76°F

Wind: 0-10 mph

Rain: 12%

Enjoy your day!

Best Time to Be Outside Tomorrow

1 PM – 2 PM93

Excellent conditions for outdoor activities (dry, comfortable temp, light wind, daylight)

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Frequently Asked Questions

What is the weather forecast for tomorrow in Rancho Cucamonga, CA?
Tomorrow in Rancho Cucamonga: High of 100°F, Low of 76°F. Clear with 12% chance of precipitation. Wind 0-10 mph.
Will it rain tomorrow in Rancho Cucamonga?
No significant precipitation expected tomorrow.
What should I wear tomorrow in Rancho Cucamonga?
With a high of 100°F and low of 76°F, check our "What to Wear" section above for specific clothing recommendations based on temperature, wind, and precipitation.
How accurate is this forecast?
Our forecasts come directly from the National Weather Service (NOAA), which provides some of the most accurate weather predictions available. Tomorrow forecasts are generally 80-90% accurate, with accuracy decreasing the further out you look. Data is refreshed every 30 minutes.