The NBACC (National Biodefence Analysis and Countermeasure Centre - a US government research laboratory), as reported in the Telegraph on 18 April, has apparently claimed that:
"Sunlight and high temperatures help stop the spread of coronavirus on hard surfaces, according to preliminary results of a study for the US Government.
"Covid-19 also struggles to survive on surfaces in high humidity, the results suggest, adding to hope that a summer heatwave could help ease the health crisis.
"A briefing by scientists working on behalf of the Department of Homeland Security at the White House reportedly found the risk of “transmission from surfaces outdoors is lower during daylight”.
“Sunlight destroys the virus quickly,” reads the document, initially leaked to the Yahoo News website.
"The results cautioned, however, that enclosed areas with low humidity, such as airplane cabins, “may require additional care to minimise risk of transmission.”...
If this report is found to be reliable and accurate and supported by other scientists, then it would appear that telling people not to go out, especially when it is very sunny, may be the opposite of what should happen.
It does seem quite logical though that being near to people who may possibly be infected should be avoided, but especially in confined indoor spaces.
It seems that there is still a lot to learn about this virus and we may be getting things wrong. It was reported in the I today that "Doctors on the frontline of China's battle against Covid 19 are increasingly baffled by a growing number of cases in which patients appear to have recovered but continue to have the coronavirus in their blood [some 70 days later]."