Is "Hot or cold temperatures prevent COVID-19" true?
Plenty of viruses fade in summer heat, so it wasn't an unreasonable guess that COVID-19 might do the same, or that cold, dry air alone might somehow keep it in check. Past experience with seasonal illness made the assumption feel almost intuitive. It didn't hold. The virus spread just as effectively through tropical heat as it did through freezing winters, in humid climates and dry ones alike, making clear that temperature was never the deciding factor in who caught it and who didn't.
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What you were taught
Hot or cold temperatures prevent COVID-19
What we know now
This myth is false. The virus that causes COVID-19 spreads from person to person regardless of temperature. People in all climates, both hot and cold, have contracted COVID-19.
Was "Hot or cold temperatures prevent COVID-19" taught in school?
Yes — and not as a joke question on a quiz. This health claim showed up in textbooks, worksheets, and classroom posters through the 2020s, which is why so many people still remember it as settled fact long after the science moved on.
Is "Hot or cold temperatures prevent COVID-19" true?
No. This myth is false. The virus that causes COVID-19 spreads from person to person regardless of temperature. People in all climates, both hot and cold, have contracted COVID-19. If you want the primary citation, start with Mayo Clinic - Debunking COVID-19 myths.
When was this understanding updated?
The evidence had largely shifted by around 2021. Schools don't flip overnight, though — plenty of classrooms kept teaching the older version for years after researchers had already moved on.