

2020 was the second-warmest year on record. The average global temperature was 0.98 °C (1.76 °F) above the 20th century average. It was also 0.02 °C (0.04 °F) below 2016, the warmest year on record.
All states, and especially in the Northeast, have become warmer over the past century. Between 1895 and 2019, the average temperature in half of US counties rose more than 2.7°F (1.5°C), a key threshold of climate warming identified by NASA.
In 1980, the average US county had good air quality 59% of days. In 2020, that rose to 88% of days. Adjusting for population change, Hawaii had the largest air quality decrease per square mile between 1980 and 2020, partly due to volcanic air pollution. California had the largest improvement.
Get more facts on the environment and climate in the US here.