UV Index
Knowledge Base articles tagged UV Index.
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What the UV Index measures — and why we need a UVA Index
The UV Index is erythemally weighted, so it's dominated by UVB and under-represents UVA. Learn exactly what the UV Index does and doesn't capture, and why a dedicated UVA Index is a useful complement.
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Why UVA changes far less with the seasons than UVB
Ozone absorbs UVB strongly and UVA barely at all, so a low winter sun collapses UVB while UVA falls only modestly. Why winter and early-morning UV is disproportionately UVA, with the numbers — and why a low UV Index never means low UVA.
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