With May 2018 ranking as the warmest such month on record in the continental U.S., beating out the Dust Bowl May of 1934, the country has extended a much longer heat streak. According to the National Oceanic and Atmospheric Administration, the country has had its warmest 3-year, 4-year, and 5-year periods on record through May 2018.
Why it matters: The unusually mild temperatures are one way that global warming is affecting the U.S., as long-term temperatures trend higher. Even if individual months fail to break a heat record, such as April 2018, the long-term trend is clear.
What they found: Recently released NOAA data show that May 2018 was 5.21 degrees Fahrenheit above the long-term average in the U.S., taking the top spot.
- Every state in the lower 48 had above average temperatures for the month, and eight states set monthly records.
- During the month, there were more than 8,590 daily warm temperature records set or tied, compared to just 460 daily cold temperature records during the same period.
The NOAA report also shows that the past 36 months, from June 2015 through May 2018, had a temperature anomaly of 2.6 degrees Fahrenheit above average, qualifying as the warmest 36-month period since reliable instrument records began in 1895.
- The past 48 months, from June 2014 through May 2018, have also been the warmest such period on record.
- The same is true for the past 60 months, dating back to June 2013.