weather

Characterizing the relationship of extreme weather events to man-made global warming is essential for crafting effective mitigation policies and adaptation strategies.

Cooling weather may have caused increased COVID-19 spread. Considered across many regions, the average reproduction number (R) gradually increased from ~1.0 to ~1.2 as daily high temperatures fell from >27 °C to ~10-15 °C (>80 °F to 50-60 °F). Other factors, including decreases in sunlight and/or UV exposure, may have slightly increased this further.