UV index in Lewisville
The UV index measures the strength of the sun's ultraviolet rays on a 0–11+ scale. Protection is recommended at 3 or higher — in southern Canada that means most midday hours from spring to early fall.
☀️ Right now
036811+
Guidance:
No protection needed for most people.
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.