UV Index for Ontario, CA

Current Ontario UV Index

1.8 (Low)

Last Updated 31 minutes ago

Hourly Ontario UV Index

The hourly Ontario, CA UV Index forecast for Sunday, August 31st, 2025.

5 Day Hourly Ontario UV Index Forecast

Last Updated 6 hours ago

The UV index forecast for the next five days in Ontario, CA has no days reaching the extreme level and 4 days reaching the high or very high levels. The peak UV intensity in Ontario over the next five days will be 9.4 on Sunday, August 31st at 1:00 pm.

The UV index forecast for Sunday, August 31st in Ontario, CA is below.

Time UV Index Risk
6pm 0.5
Low
7pm 0
Low
8pm 0
Low
9pm 0
Low
10pm 0
Low
11pm 0
Low

The UV index forecast for Monday, September 1st 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 0.1
Low
8am 0.8
Low
9am 2.2
Low
10am 4.4
Moderate
11am 6.7
High
12pm 8.5
Very High
1pm 9.1
Very High
2pm 8.2
Very High
3pm 6.1
High
4pm 3.8
Moderate
5pm 1.7
Low
6pm 0.5
Low
7pm 0
Low
8pm 0
Low
9pm 0
Low
10pm 0
Low
11pm 0
Low

The UV index forecast for Tuesday, September 2nd 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 0.1
Low
8am 0.8
Low
9am 2.1
Low
10am 4.3
Moderate
11am 6.3
High
12pm 8.3
Very High
1pm 9
Very High
2pm 6.7
High
3pm 5.9
Moderate
4pm 2.7
Low
5pm 1.2
Low
6pm 0.4
Low
7pm 0
Low
8pm 0
Low
9pm 0
Low
10pm 0
Low
11pm 0
Low

The UV index forecast for Wednesday, September 3rd 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 0.1
Low
8am 0.6
Low
9am 2.1
Low
10am 4.3
Moderate
11am 6.6
High
12pm 8.4
Very High
1pm 9
Very High
2pm 8.1
Very High
3pm 6.2
High
4pm 3.8
Moderate
5pm 1.7
Low
6pm 0.5
Low
7pm 0
Low
8pm 0
Low
9pm 0
Low
10pm 0
Low
11pm 0
Low

The UV index forecast for Thursday, September 4th 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