May was 2nd-wettest month on record

While temperatures remained average overall in the contiguous U.S. in May, extremes were seen on both sides, the NOAA said. The Southeast was hit with particularly hot temperatures, while the Southwest and the northern Plains had colder weather.

In Alaska, the average May temperature was 42.9 degrees Fahrenheit, 5.1 degrees above the long-term mean and making it the sixth-warmest May on record for the state.

On Tuesday, the NOAA also announced it recorded the highest carbon-dioxide levels in its history. C02 levels tend to be highest during May, and this year’s part per million (ppm) count, at 414.7, broke records.

Annual increases measured at an observatory in Hawaii initially averaged carbon-dioxide increases of about 0.7 ppm per year, which rose to about 1.6 ppm per year in the 1980s and 1.5 ppm per year in the 1990s,” the NOAA said. “The growth rate rose to 2.2 ppm per year during the last decade.”

Higher levels of carbon dioxide are linked to hotter global temperatures and other effects of climate change, such as rising seas and unusual weather patterns.