Question & Answer

Is the transmission of COVID-19 effected by hot or humid weather?

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There are claims on social media that hot or humid weather can reduce the transmission of COVID-19. These claims have grown in Ireland, particularly with recent good weather.

  • The World Health Organization says that “exposing yourself to the sun or to temperatures higher than 25C degrees does not prevent the coronavirus disease (COVID-19)”.
  • Cases of COVID-19 have been reported in countries that have hot and humid weather.
  • Although some studies have suggested that temperature may influence the transmission of COVID-19, the evidence overall is inconclusive.
  • COVID-19 transmission may have reduced as we experience warmer weather, but we are also seeing the effects of public isolation policy, reduced migration and other preventative measures such as physical distancing and hand hygiene measures. It is far more likely that these measures are reducing the rate of transmission.
  • The current recommendations to prevent transmission of COVID 19 include: washing your hands well and often; covering your mouth and nose with a tissue or sleeve when coughing or sneezing and then safely throw away any used tissue where others will not touch it. Avoid touching your eyes, nose and mouth with unwashed hands. Clean and disinfect frequently touched objects and surfaces. Avoid shaking hands or hugging when saying hello and greeting other people. Distance yourself at least 2 metres away from other people, especially those who might be unwell.

Things to Remember


  • Lead Researchers: Claire Beecher, HRB-Trials Methodology Research Network & Evidence Synthesis Ireland, NUI Galway; Fiona Quirke, HRB-NEPTuNE, HRB-Trials Methodology Research Network, NUI Galway.
  • Reviewed by: Prof Declan Devane, School of Nursing and Midwifery, HRB-Trials Methodology Research Network, Evidence Synthesis Ireland & Cochrane Ireland, NUI Galway.
  • Evidence Advisor: Dr Imcha Mendinaro, UL Hospitals Group, Limerick.
  • Evidence Advisor: Deirdre Mac Loughlin, PPI Ignite, NUI Galway.
  • Journalist Advisor: Dr Claire O’Connell, Contributor, The Irish Times.