UV Index in Ottawa, United States

Last updated: June 2, 2025

Understanding the UV Index is crucial for residents of Ottawa, United States, as it directly impacts your skin health and sunburn risk. With the city’s Cfa climate, the sun can be surprisingly strong, especially during peak hours. On days with a high UV Index, such as 11 at noon and 13 in the early afternoon, it’s vital to be aware of your exposure levels. By staying educated about UV risks, you can take proactive measures to protect your skin and enjoy the outdoors safely. Remember, even on overcast days, UV rays can still penetrate the clouds, making awareness key to safeguarding your health!

Hourly UV Index in Ottawa

The UV Index reveals a dynamic daily pattern, starting from a low of 1 at 7:00 AM, and gradually climbing to a peak of 11 between 1:00 PM and 2:00 PM. As the sun reaches its zenith, 12:00 PM also sees a high of 10, signaling an urgent need for sun protection. After this peak, a downward trend persists, with readings dropping to 7 by 4:00 PM, and further declining to 1 by 7:00 PM. This data underscores the importance of remaining vigilant about UV exposure during the midday hours when the risk is greatest, highlighting the necessity of precautions like sunscreen and protective clothing.

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	2	low	45 min
09:00	3	moderate	30 min
10:00	5	moderate	30 min
11:00	8	very high	15 min
12:00	10	very high	15 min
13:00	11	extreme	10 min
14:00	11	extreme	10 min
15:00	9	very high	15 min
16:00	7	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