Ontario, CA Weather Forecast
Right now it is 72°F and clear in Ontario (as of Tue, 11:30 AM PST). Today: high near 72°F. Tomorrow: sunny, high near 73°F. Official NWS forecast and alerts, refreshed every 30 minutes.
Current conditions
Measured at Ontario International Airport (3 mi from the city center).
Weather tomorrow in Ontario
Sunny73°FSunny, with a high near 73. South wind 0 to 5 mph.
Mostly Clear55°FMostly clear, with a low around 55. North wind 0 to 5 mph.
Weather alerts
No active National Weather Service watches, warnings or advisories for Ontario right now.
7-day forecast
Mostly Sunny72°F / 54°FMostly sunny, with a high near 72. Southwest wind 5 to 10 mph. Tonight: Mostly clear, with a low around 54. Northwest wind 0 to 5 mph.
Sunny73°F / 55°FSunny, with a high near 73. South wind 0 to 5 mph. Wednesday Night: Mostly clear, with a low around 55. North wind 0 to 5 mph.
Sunny77°F / 55°FSunny, with a high near 77. East wind 0 to 5 mph. Thursday Night: Mostly clear, with a low around 55.
Sunny80°F / 57°FSunny, with a high near 80. Friday Night: Clear, with a low around 57.
Sunny83°F / 60°FSunny, with a high near 83. Saturday Night: Clear, with a low around 60.
Sunny84°F / 61°FSunny, with a high near 84. Sunday Night: Partly cloudy, with a low around 61.
Mostly Sunny81°F / 60°FMostly sunny, with a high near 81. Monday Night: Partly cloudy, with a low around 60.
Forecast issued by NWS forecast office SGX · updated Nov 3, 10:34 AM PST. Daytime highs and overnight lows are on the right.
Hourly forecast, radar & more on weather.gov
Nearby cities
Ontario population: 187,013 (U.S. Census Bureau, July 1, 2025 estimate). More California cities · All US cities
Source: National Weather Service / NOAA (public domain), fetched live. Tachlis is not affiliated with the NWS.
Questions & answers
What is the weather tomorrow in Ontario?
Wednesday, November 4: Sunny, high near 73°F; night: mostly clear, low around 55°F.
Where does the Ontario forecast come from?
From the National Weather Service forecast office SGX, which writes the official forecast for Ontario's 2.5 km grid square. Current conditions come from the nearest NWS/FAA weather station.
How often is the Ontario weather updated?
This page fetches fresh data from the National Weather Service at most every 30 minutes, and checks for new watches and warnings every 5 minutes.
What time zone are the times shown in?
Local time for Ontario (America/Los Angeles).
Why can the current temperature differ from the forecast?
The current reading is a real measurement at a weather station, often at an airport, while the forecast describes the whole grid square around the city. Temperatures can differ by a few degrees across a city.