Stories

Hot streak: U.S. sets records for warmest 3, 4, and 5-year periods

Temperature rankings for the U.S. during the past 48 months, showing extensive, record warmth.
Temperature rankings for the contiguous U.S. during the past 48 months. Credit: NOAA/NCEI.

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.