UV Index in Ottawa, United States

Last updated: August 1, 2025

Understanding the UV Index is crucial for safeguarding your skin health in Ottawa, where the weather can range from sunny summers to overcast winters. With the UV Index peaking at 10 during the summer months, awareness of these levels helps in preventing sunburn and protecting against long-term skin damage. Ottawa's Cfa climate brings about substantial UV exposure, especially between 11 AM and 3 PM, when the sun's rays are strongest. Stay informed and enjoy the outdoors safely by paying attention to daily UV Index updates!

Hourly UV Index in Ottawa

Starting off the day, the UV Index at 7:00 AM was a safe 1, gradually climbing to 2 by 8:00 AM. As the sun rose higher, it peaked at a striking 10 between 1:00 PM and 2:00 PM, indicating a significant risk for harmful effects on unprotected skin. The intensity of UV radiation began to wane in the afternoon, dropping to 9 at 3:00 PM and steadily decreasing to 4 by 5:00 PM. As evening approached, the index fell further to 2 at 6:00 PM and capped the day at a low 1 by 7:00 PM. This hourly trend highlights the importance of sun protection during peak hours, particularly between 11:00 AM and 2:00 PM, when the UV Index is at its highest.

Average solar exposure data for the current time of the year. Actual values may vary and depend on many factors, such as cloud cover, vegetation cover, surface type, etc.
Time	UVI	Category	Time to Burn
07:00	1	low	45 min
08:00	1	low	45 min
09:00	2	low	45 min
10:00	4	moderate	30 min
11:00	7	high	25 min
12:00	9	very high	15 min
13:00	10	very high	15 min
14:00	10	very high	15 min
15:00	8	very high	15 min
16:00	6	high	25 min
17:00	4	moderate	30 min
18:00	2	low	45 min
19:00	1	low	45 min

Monthly UV Index Trends in Ottawa

Throughout the year, seasonal UV changes present varying risks for sun exposure. The high-risk months typically occur from April to August, when the UV Index rises to 9 or above, indicating very high to extreme exposure levels. Specifically, June and July see the most critical levels at 11, suggesting a burn time of just 10 minutes. Visitors and residents should be particularly vigilant during these months, applying sunscreen with a high SPF, wearing protective clothing, and seeking shade during peak sun hours. As the UV Index decreases from September to December, with values dropping back to 3-6, precautions remain advisable but can be somewhat relaxed, particularly in the winter months.

Monthly Maximum UV Index for Ottawa, United States

The monthly maximum UV Index (UVI) represents the highest UV radiation level recorded each month in Ottawa. It measures the strength of ultraviolet radiation from the sun and helps assess the risk of sunburn and UV-related health issues.

Data source: Statistical UV Index data for Ottawa, based on information from the Copernicus Climate Change Service.

UV Risk Categories

Extreme (11+): Avoid the sun, stay in shade.
Very High (8-10): Limit sun exposure.
High (6-7): Use SPF 30+ and protective clothing.
Moderate (3-5): Midday shade recommended.
Low (0-2): No protection needed.

Compare Ottawa UV Index with Other United States Cities

The table above highlights how UV exposure in Ottawa compares to other major locations across United States. This comparison helps travelers and residents better understand regional sun intensity and plan outdoor activities with sun safety in mind.

Ottawa's solar exposure compared to other cities in United States. Generated using Copernicus Atmosphere Monitoring Service information.
	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Chicago UVI	3	4	6	8	9	10	10	9	8	6	4	2
Brooklyn UVI	3	5	6	8	10	10	9	9	8	6	4	2
New York City UVI	3	5	6	8	10	10	9	9	8	6	4	2
Ottawa	3	6	7	9	10	11	11	10	9	7	4	3
Los Angeles UVI	4	6	8	9	10	11	11	10	10	7	5	4
Houston UVI	5	8	9	11	11	12	12	11	10	9	7	5