The World Health Organisation has stated that exposure to the sun or temperatures higher than 25°C does not prevent coronavirus disease.
WHO has clarified that no matter how sunny or hot the weather is, coronavirus does not die from exposure temperatures higher than 25°C degrees.
BBC's article mentions that changes in temperature and humidity affect how long the coronavirus can survive on surfaces and more investigation is necessary to study the effect of temperature and humidity on the new virus.
The COVID-19 pandemic has given rise to a lot of potentially dangerous misinformation. For reliable advice on COVID-19 including symptoms, prevention and available treatment, please refer to the World Health Organisation or your national healthcare authority.