London Daily

Focus on the big picture.
Tuesday, Oct 14, 2025

Does warm weather mean you are less likely to catch Covid?

Does warm weather mean you are less likely to catch Covid?

According to epidemiologists, meeting outside helps minimise infection risks but heat itself has a negligible effect on the virus

With the recent rising temperatures and more people now mixing outdoors as restrictions have been lifted in England, and eased in Scotland, Wales and Northern Ireland, experts explain how much of an effect the weather has on Covid-19.

Does the hot weather have an impact on Covid?


Studies show that the season, and the temperature, does have an impact on the spread of the coronavirus but that impact is not significant.

Prof John Edmunds, a member of the Scientific Advisory Group for Emergencies (Sage), said the evidence showed that warmer temperatures affected transmission, but the impact was small as most transmission occurred inside.

“Transmission outside is minimal,” said Edmunds, an epidemiologist at the London School of Hygiene & Tropical Medicine. “Most transmission happens in enclosed settings. If it’s sunny outside viruses will die quicker, but they wouldn’t have lasted very long in any case.”

A recent study led by Imperial College and conducted on US data found higher temperatures were associated with lower transmission rates, if there were no other measures in place such as lockdowns and mask wearing. The Imperial study found that a 20 degree difference – typical between summer and winter – would probably see a change in the reproduction number of 0.8.

“From an epidemiological perspective this change can be significant,” said one of the study’s co-authors, Dr Ilaria Dorigatti. “[But] in presence of interventions climatic factors play a negligible role.”

So why do other viruses such as the flu flourish in winter?


Because even a small increase in a relatively low R number can make a difference, according to Edmunds.

“Vaccination or [natural] immunity will bring the reproduction number right down or immunity in the population. So a small change can allow the reproduction number to go slightly above one, or slightly below one. In the winter if it is slightly above one you get winter epidemics, and if in summer it is slightly below one, less so.”

Do UV rays kill the coronavirus?


Yes, but as most transmission of Covid was indoors, again the difference was slight, said Edmunds. “UV does kill viruses. So higher UV is bad for the virus, but that only really matters outside. And given that almost no transmission occurs outside anyway, it doesn’t make a lot of difference,” he said.

Dorigatti said the Imperial study focused on temperature and did not specifically look at UV but other studies by the Yale professor Yiqun Ma and others had found higher UV rates could have a role to play in reducing transmission rates.

Does the type of heat impact transmissibility?


One study by scientists in China, yet to be peer reviewed, suggested mortality rates were lower on days when the humidity levels and temperatures were higher. Dorigatti said other studies by Mohammad M Sajadi and Yiqun Ma had found a role for humidity, with lower humidity associated with higher transmission rates, implying that humid heat may reduce transmission more than dry heat.

Can we worry less about Covid in warmer weather?


In short, no. Dr Will Pearse, another researcher on the Imperial study, said the critical message was that the weather was only a small factor in the spread of Covid.

“I would really strongly encourage people to not think: ‘OK, it’s warm weather outside, so I don’t need to worry about Covid,’” he said. “We’ve seen what the situation looks like in places warmer than the UK and in places colder than the UK. Warm weather is no substitute for mitigation.”

Kathleen O’Reilly, an epidemiologist with the London School of Hygiene & Tropical Medicine, said: “Hopefully most people will be sensible and pragmatic; meeting outdoors will minimise Covid-19 infection risk but staying out of direct sunlight, especially at midday, is still important. Meeting indoors but ensuring good ventilation will be good to minimise infection risk and also to keep cool,” she said.

Newsletter

Related Articles

0:00
0:00
Close
EU Deploys New Biometric Entry/Exit System: What Non-EU Travelers Must Know
Australian Prime Minister’s Private Number Exposed Through AI Contact Scraper
Ex-Microsoft Engineer Confirms Famous Windows XP Key Was Leaked Corporate License, Not a Hack
China’s lesson for the US: it takes more than chips to win the AI race
Australia Faces Demographic Risk as Fertility Falls to Record Low
California County Reinstates Mask Mandate in Health Facilities as Respiratory Illness Risk Rises
Israel and Hamas Agree to First Phase of Trump-Brokered Gaza Truce, Hostages to Be Freed
French Political Turmoil Elevates Marine Le Pen as Rassemblement National Poised for Power
China Unveils Sweeping Rare Earth Export Controls to Shield ‘National Security’
The Davos Set in Decline: Why the World Economic Forum’s Power Must Be Challenged
France: Less Than a Month After His Appointment, the New French Prime Minister Resigns
Hungarian Prime Minister Viktor Orbán stated that Hungary will not adopt the euro because the European Union is falling apart.
Sarah Mullally Becomes First Woman Appointed Archbishop of Canterbury
Mayor in western Germany in intensive care after stabbing
Australian government pays Deloitte nearly half a million dollars for a report built on fabricated quotes, fake citations, and AI-generated nonsense.
US Prosecutors Gained Legal Approval to Hack Telegram Servers
Macron Faces Intensifying Pressure to Resign or Trigger New Elections Amid France’s Political Turmoil
Standard Chartered Names Roberto Hoornweg as Sole Head of Corporate & Investment Banking
UK Asylum Housing Firm Faces Backlash Over £187 Million Profits and Poor Living Conditions
UK Police Crack Major Gang in Smuggling of up to 40,000 Stolen Phones to China
BYD’s UK Sales Soar Nearly Nine-Fold, Making Britain Its Biggest Market Outside China
Trump Proposes Farm Bailout from Tariff Revenues Amid Backlash from Other Industries
FIFA Accuses Malaysia of Forging Citizenship Documents, Suspends Seven Footballers
Latvia to Bar Tourist and Occasional Buses to Russia and Belarus Until 2026
A Dollar Coin Featuring Trump’s Portrait Expected to Be Issued Next Year
Australia Orders X to Block Murder Videos, Citing Online Safety and Public Exposure
Three Scientists Awarded Nobel Prize in Medicine for Discovery of Immune Self-Tolerance Mechanism
OpenAI and AMD Forge Landmark AI-Chip Alliance with Equity Option
Munich Airport Reopens After Second Drone Shutdown
France Names New Government Amid Political Crisis
Trump Stands Firm in Shutdown Showdown and Declares War on Drug Cartels — Turning Crisis into Opportunity
Surge of U.S. Billionaires Transforms London’s Peninsula Apartments into Ultra-Luxury Stronghold
Pro Europe and Anti-War Babiš Poised to Return to Power After Czech Parliamentary Vote
Jeff Bezos Calls AI Surge a ‘Good’ Bubble, Urges Focus on Lasting Innovation
Japan’s Ruling Party Chooses Sanae Takaichi, Clearing Path to First Female Prime Minister
Sean ‘Diddy’ Combs Sentenced to Fifty Months in Prison Following Prostitution Conviction
Taylor Swift’s ‘Showgirl’ Launch Extends Billion-Dollar Empire
Trump Administration Launches “TrumpRx” Plan to Enable Direct Drug Sales at Deep Discounts
Trump Announces Intention to Impose 100 Percent Tariff on Foreign-Made Films
Altman Says GPT-5 Already Outpaces Him, Warns AI Could Automate 40% of Work
Singapore and Hong Kong Vie to Dominate Asia’s Rising Gold Trade
Trump Organization Teams with Saudi Developer on $1 Billion Trump Plaza in Jeddah
Manhattan Sees Surge in Office-to-Housing Conversions, Highest Since 2008
Switzerland and U.S. Issue Joint Assurance Against Currency Manipulation
Electronic Arts to Be Taken Private in Historic $55 Billion Buyout
Thomas Jacob Sanford Named as Suspect in Deadly Michigan Church Shooting and Arson
Russian Research Vessel 'Yantar' Tracked Mapping Europe’s Subsea Cables, Raising Security Alarms
New York Man Arrested After On-Air Confession to 2017 Parents’ Murders
U.S. Defense Chief Orders Sudden Summit of Hundreds of Generals and Admirals
Global Cruise Industry Posts Dramatic Comeback with 34.6 Million Passengers in 2024
×