UV Index for Ontario, CA

Current Ontario UV Index

0 (Low)

Last Updated 19 minutes ago

Hourly Ontario UV Index

The hourly Ontario, CA UV Index forecast for Wednesday, September 17th, 2025.

5 Day Hourly Ontario UV Index Forecast

Last Updated 10 hours ago

The UV index forecast for the next five days in Ontario, CA has no days reaching the extreme level and 3 days reaching the high or very high levels. The peak UV intensity in Ontario over the next five days will be 8.2 on Friday, September 19th at 1:00 pm.

The UV index forecast for Wednesday, September 17th in Ontario, CA is below.

Time UV Index Risk
10pm 0
Low
11pm 0
Low

The UV index forecast for Thursday, September 18th in Ontario, CA is below.

Time UV Index Risk
12am 0
Low
1am 0
Low
2am 0
Low
3am 0
Low
4am 0
Low
5am 0
Low
6am 0
Low
7am 0
Low
8am 0.1
Low
9am 0.7
Low
10am 1
Low
11am 1
Low
12pm 3
Moderate
1pm 4
Moderate
2pm 5.4
Moderate
3pm 3.4
Moderate
4pm 2.2
Low
5pm 1.2
Low
6pm 0.2
Low
7pm 0
Low
8pm 0
Low
9pm 0
Low
10pm 0
Low
11pm 0
Low

The UV index forecast for Friday, September 19th in Ontario, CA is below.

Time UV Index Risk
12am 0
Low
1am 0
Low
2am 0
Low
3am 0
Low
4am 0
Low
5am 0
Low
6am 0
Low
7am 0
Low
8am 0.4
Low
9am 1.5
Low
10am 3.4
Moderate
11am 5.8
Moderate
12pm 7.6
High
1pm 8.2
Very High
2pm 7.3
High
3pm 5.4
Moderate
4pm 3.2
Moderate
5pm 1.3
Low
6pm 0.3
Low
7pm 0
Low
8pm 0
Low
9pm 0
Low
10pm 0
Low
11pm 0
Low

The UV index forecast for Saturday, September 20th in Ontario, CA is below.

Time UV Index Risk
12am 0
Low
1am 0
Low
2am 0
Low
3am 0
Low
4am 0
Low
5am 0
Low
6am 0
Low
7am 0
Low
8am 0.5
Low
9am 1.7
Low
10am 3.7
Moderate
11am 5.9
Moderate
12pm 7.6
High
1pm 8.1
Very High
2pm 7.3
High
3pm 5.4
Moderate
4pm 3.1
Moderate
5pm 1.3
Low
6pm 0.3
Low
7pm 0
Low
8pm 0
Low
9pm 0
Low
10pm 0
Low
11pm 0
Low

The UV index forecast for Sunday, September 21st in Ontario, CA is below.

Time UV Index Risk
12am 0
Low
1am 0
Low
2am 0
Low
3am 0
Low
4am 0
Low
5am 0
Low