August 12, 2026 · Ottawa, Canada
Capital812,129 people
See today's UV index in Ottawa hour by hour below. The UV index shows how strong the sun's ultraviolet radiation is — the higher the number, the faster skin can burn. Values are calculated for Ottawa's coordinates and updated daily.
UV has dropped for today
Protection windowClear sky
Daylight: sunrise 06:01 – sunset 20:17
Tomorrow: UV 6 at its peak around 13:00
The UV index in Ottawa peaks at 5 (moderate) around 13:00 today. Sun protection is recommended between 10:27 and 15:36, while the index stays at 3 or above. Cloud cover is damping the peak by roughly 12% compared with a clear sky. Tomorrow the index is forecast to peak at 6 around 13:00.
| Time | UV index | Level |
|---|---|---|
| 06:00 | 0 | Low |
| 07:00 | 0.2 | Low |
| 08:00 | 0.6 | Low |
| 09:00 | 1.5 | Low |
| 10:00 | 2.5 | Low |
| 11:00 | 3.6 | Moderate |
| 12:00 | 4.3 | Moderate |
| 13:00 | 5.1 | Moderate |
| 14:00 | 5.1 | Moderate |
| 15:00 | 3.9 | Moderate |
| 16:00 | 2.4 | Low |
| 17:00 | 1.5 | Low |
| 18:00 | 0.7 | Low |
| 19:00 | 0.2 | Low |
| 20:00 | 0 | Low |
| 21:00 | 0 | Low |
Ottawa lies at 45°N. The midday sun reaches 59.5° above the horizon in Ottawa today, against a yearly ceiling of 68.0°. Elevation is what sets the ceiling for UV, and over Ottawa it is high enough for the index to reach very high values through the summer months.
The UV index is an international scale describing the strength of the sun's ultraviolet radiation at ground level. It starts at 0 and is effectively open-ended — at mid-latitudes it rarely exceeds 8, while in the tropics and high in the mountains it can pass 11. The higher the number, the less time it takes to get sunburnt.
The UV index depends mainly on how high the sun is in the sky. That is why it peaks around solar noon and is greatest in summer near the longest day of the year. Clouds, ozone, altitude and reflection from snow or water also affect the value.
| UV index | Level | Recommendation |
|---|---|---|
| 0–2 | Low | No special protection needed. |
| 3–5 | Moderate | Use sunscreen (SPF 30+), seek shade around midday. |
| 6–7 | High | Sunscreen, hat and sunglasses. Avoid the sun 12:00–15:00. |
| 8–10 | Very high | Extra protection. Limit midday sun exposure. |
| 11+ | Extreme | Avoid the sun at midday. Full protection required. |