Laboratory studies have shown that SARS-CoV-2 – the causative pathogen of COVID-19 – is not very stable in warmer temperatures and high humidity. Other studies have found both positive and negative associations between the weather and viral transmission, based on daily confirmed case statistics.
However, using daily positive cases may not be very useful in studying the climate’s effect of SARS-CoV-2’s transmission. For instance, this data does not include the many cases that go undocumented, the lag between infection and symptom onset and the lag between testing and reporting. Additionally, many studies have not controlled for other confounding factors such as the implementation of health interventions, socioeconomic factors and other environmental factors.