Monthly Climate Reports | National Climate Report | May 2026

The May 2026 report highlights that the month was the second-warmest on record globally, with carbon dioxide levels reaching a new monthly peak of 432.3 ppm. In the United States, spring 2026 was the second-warmest on record for the contiguous U.S., while 77% of the region experienced abnormally dry or drought conditions as of early June. The report also notes a developing potentially very strong El Niño and record-low snowpack in several western states.

• May 2026 was the second-warmest month on record globally for combined land and ocean temperatures, with the Northern Hemisphere ranking fourth-warmest and the Southern Hemisphere second-warmest.
• Atmospheric carbon dioxide concentrations reached a new monthly record of 432.3 parts per million at Mauna Loa, Hawaii, in May 2026, an increase of approximately 1.8 ppm over the previous year.
• The contiguous United States experienced its second-warmest spring on record in 2026, with Arizona, Colorado, New Mexico, and Texas each recording their warmest spring ever.
• Severe drought conditions affected at least 77% of the contiguous U.S. by June 2, 2026, with record-low maximum snowpack observed in Colorado, New Mexico, Utah, and Wyoming.
• Hawaii experienced its wettest spring on record in 2026, receiving 34.42 inches of precipitation, which was 215.9% of the normal amount.
• Climate Central's Climate Shift Index (CSI) indicates that human-caused climate change drove summertime warming trends in 91% of analyzed U.S. cities, with exceptional warmth (CSI 5) noted in San Juan, Puerto Rico and Sarasota, Florida in May.
• Predictions from the North American Multi-Model Ensemble (NMME) suggest global temperatures could approach 1.9°C above pre-industrial levels by late 2026 or early 2027, driven by a potentially very strong El Niño.

APA

Climate Central (2026). Monthly Climate Reports | National Climate Report | May 2026. https://www.climatecentral.org/climate-briefings/may-2026

Chicago

Climate Central. Monthly Climate Reports | National Climate Report | May 2026. 2026. https://www.climatecentral.org/climate-briefings/may-2026.

Wikipedia

{{cite report |author=Climate Central |title=Monthly Climate Reports | National Climate Report | May 2026 |date=May 2026 |url=https://www.climatecentral.org/climate-briefings/may-2026 |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{climatecentral2026monthly, author = {{Climate Central}}, title = {{Monthly Climate Reports | National Climate Report | May 2026}}, institution = {Climate Central}, year = {2026}, month = may, url = {https://www.climatecentral.org/climate-briefings/may-2026}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }