Overall results

Our findings provide evidence for the relationship between several weather variables and the spread of COVID-19.

However, the (conservatively) estimated relationships are not strong enough to seasonally control the epidemic in most locations.

  • Each degree Celsius above 25 C is associated with 3.8% lower reproduction number (2% per degree Farenheit above 77 F).
  • Ultraviolet has a U-shaped relationship with transmission. At a low/moderate UV of 3 (EPA standard), a unit higher UV is associated with 3.5% lower reproduction number, while at a very high UV of 10, a unit higher UV is correlated with 4% higher reproduction number.
  • With one standard deviation increase in each of the following variables we observed increases in reproduction number: 1.4% (0.4-2.4%) for diurnal temperature, 1.3% (0.3-2.4%) for air pressure (P),  1.4% (0.4-2.5%) for log-transformed wind speed, 2.7% (1.7-3.8%) for log-transformed precipitation, 2.4% (1.1-3.6%) for log-transformed Ozone and 2.9% (1.1-4.6%) for log-transformed Sulfur Dioxide.

Detailed results 

All data, codes, analysis details, assumptions, and sensitivity results are available in Resources. (Note: This study is not peer reviewed yet.) 

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