365 Days of Climate Awareness 175 – 2021 State of the Climate, North America

2021 US Climate Data

• Mauna Loa atmospheric CO₂ concentration: 416.45 ppm, +2.21 ppm from 2020 (preliminary; Mauna Loa only)
• Average air temperature: 55.9°F, 7^th all-time 1895-2021
• Average precipitation: 30.48”, +0.54” over mean
• Tornadoes: 1376 (preliminary count), 125 (10%) above the 1991-2010 average 1251
• 21 named tropical cyclones: 7 hurricanes, 4 major (winds > 111 mph, 3-5 Saffir-Simpson)
• Atlantic ACE: 194.59 x 10⁴ kts² (1991 - 2020 mean: 145 x 10⁴ kts²)
• ENSO: La Niña 

Larger Version

North American Conditions

• Warmer than average: Canada; the continental US; Mexico
• Cooler than average: Alaska
• Drier than average: Northwestern and mid-Atlantic US
• Wetter than average: Southeastern and northeastern US
• Snow cover: 16.24 x 10⁶ km² winter maximum vs 1966 - 2020 average 15.1 x 10⁶ km²  

Severe drought affected a record area of the United States in 2021. According to the US Drought Monitor, the minimum area affected by drought occurred in May at 43.4%, and the maximum in December at 55.5%. The Drought Monitor is an association of land and atmospheric scientists based at the University of Nebraska-Lincoln, tasked with monitoring, mapping and predicting drought behavior throughout the United States. They issue a series of ratings based on the local conditions:

1. D0 = abnormally dry;
2. D1 = moderate drought
3. D2 = severe drought
4. D3 = extreme drought
5. D4 = exceptional drought

In August 2021, D3 and D4 conditions existed throughout 26.8% of the continental US, a record, primarily throughout the southwest.

2021 US Percentage Area Very Warm vs Very Cold (top 10th percentile of each)

2021 was also the third-most expensive year in US history for climate and weather disasters, totaling $145B, which included $75B for Hurricane Ida alone. After making landfall as a category 4 storm in Louisiana on August 29, Ida moved north, merged with a frontal system over land and brought high wind, extreme rain and tornadoes to the Northeast in the first days of September.

2021 US Percentage Area Very Wet vs Very Dry (top 10th percentile of each)

The US Drought Monitor

Tomorrow: the 2021 state of the world climate.

Be brave, and be well.