UV index
UV peaks from late spring through summer. In June and July the index often reaches 8 or more in southern Ontario, the Prairies and southern BC, and it runs higher at altitude and off water, sand or snow — spring skiers in the Rockies burn fast.
Low 1-2Moderate 3-5High 6-7Very high 8-10Extreme 11+
UV across the country today
The strongest sun among the cities we track today is over London, ON, where the index peaks near 6. None of them reach the very-high band today. The index tracks the sun's angle, not the heat: it peaks within an hour of solar noon, runs higher at altitude, and fresh snow can reflect up to 80% of it back at you.