The World Health Organization said that ultraviolet (UV) radiation and heat are different forces that require distinct approaches to personal protection [1].

This distinction is critical because relying on temperature to determine sun safety can lead to severe skin damage and long-term health complications. Because UV radiation is invisible, people may remain unprotected during cool but high-UV days, increasing their susceptibility to burns and cancer [1, 2].

UV intensity typically peaks around midday, often occurring before the day's highest temperatures are reached [1]. This gap means a person could experience peak radiation exposure before they feel the full heat of the afternoon. In regions currently experiencing heatwaves, such as Morocco, high UV levels have raised significant public health concerns [4].

Experts said checking the UV Index rather than a thermometer determines the necessary level of protection. The UV index ranges from zero to 11-plus, with higher values indicating a greater risk of skin damage and sunburn [3].

Failure to monitor these levels has tangible consequences for public health. In the UK, melanoma has become the fifth most common cancer [2]. The risk is cumulative over a lifetime of exposure.

"Every exposure to UV, especially every sunburn, increases our risk of skin cancer," Prof. Dorothy Bennett said [2].

To mitigate these risks, the WHO suggests using sunscreens, wearing protective clothing, and seeking shade during peak hours regardless of the ambient temperature [1].

“UV radiation and heat both come from the sun but are not the same.”

The disconnect between perceived heat and actual UV intensity creates a dangerous 'safety illusion' for the public. By decoupling temperature from radiation risk, the WHO is shifting the public health narrative from comfort-based protection to data-driven protection via the UV Index, aiming to reduce the rising global incidence of melanoma.