The National Oceanic and Atmospheric Administration (NOAA) has announced that 2012 was not just the hottest year on record for the contiguous United States, but also had the second most “extreme” weather in recorded history.
Extreme weather was calculated using the U.S. Climate Extremes Index, which generates a numerical score based on extremes in temperature, precipitation and landfalling tropical cyclones. The 2012 score was nearly 100 percent higher than average, and was surpassed only by 1998.
Every state hotter than average
The overall average yearly temperature for 2012 was 55.3°F, surpassing the 20th century average by 3.2°. It surpassed the prior record hottest year, 1998, by 1.0°. Annual temperatures were above average in every one of the contiguous states. In 19 states, 2012 was the hottest year ever recorded; in 26 states, it was the second hottest.
In fact, every single season in 2012 was hotter than average. The year began with the fourth warmest winter ever recorded, which led to the third smallest snow cover on record. Across the central and southern Rocky Mountains, in fact, snowpack totals were lower than 50 percent of normal. Low levels and retention of snowfall meant less available water later in the year.
Winter turned to spring with the warmest March ever recorded. Spring temperatures averaged 5.2° higher than normal, making it the hottest spring on record by a whopping 2.0°. This produced an early starting growing season, which led to early depletion of water from soil and laid the groundwork for a coming historic drought. Temperatures continued to break records in the summer, and July was actually the hottest month ever recorded in the contiguous United States, with an average temperature of 76.9° (3.6° higher than average). Autumn, too, was hotter than average.
Overall, 99.1 million people, nearly one-third the U.S. population, experienced 10 or more days of weather hotter than 100° this past year.