ALLENTOWN, Pa. — The planet just finished its warmest month in the instrumental record. The National Weather Service gauge at Lehigh Valley International Airport recorded an August half a degree cooler than normal.
Both things are true, and the gap between them is the local story in this week’s global heat findings.
The European Union’s Copernicus Climate Change Service reported that August averaged 16.96 degrees Celsius (62.53 degrees Fahrenheit) worldwide, 1.65 degrees Celsius above the 1850-1900 preindustrial baseline and tied with July 2023 as the hottest month measured, Euronews reported. It was the first month since November 2025 to exceed the 1.5-degree mark written into the 2015 Paris agreement. Copernicus’ bulletin also rated June through August the joint-warmest such period on record globally, on par with 2024.
“August 2026 was a remarkable month in the global climate record,” said Samantha Burgess, strategic lead for climate at the European Centre for Medium-Range Weather Forecasts. “It was both the warmest August and the warmest month ever recorded.”
NOAA’s National Centers for Environmental Information reported that the contiguous United States averaged 75.6 degrees in August, the warmest August in its 132-year record, and that the June-through-August period beat the previous U.S. records, set in 1936 and 2021, by four-tenths of a degree.
Pennsylvania was not part of that. The state’s summer averaged 69.8 degrees, according to NOAA’s statewide time series — 29th-warmest of the 132 summers on file, and 1.7 degrees short of the 2005 record.
The Allentown station’s own ledger says the same thing in finer print. The Mount Holly forecast office’s monthly climate summary for August puts the airport’s mean temperature at 73.1 degrees against a 1991-2020 normal of 73.6. The average high, 83 degrees, ran 1.3 below normal. The station logged two days at 90 or above; normal is five.
Cooling degree days — the utility industry’s measure of air-conditioning load — totaled 260 for the month against a normal of 268. Across the three summer months, the office’s June, July and August reports add to 779 against a normal of 792. June ran two-tenths above normal with six 90-degree days, three more than normal. July ran four-tenths below.
The exception was a single week. Between June 29 and July 5, the Pennsylvania Department of Health recorded 1,345 heat-related illness emergency department visits statewide, peaking at 335 on July 3, a department spokesperson told the Pennsylvania Capital-Star.
Northampton County opened nine senior centers as cooling stations, in Bethlehem, Easton, Nazareth, Hellertown, Bangor and Cherryville; county officials said the air-conditioned spaces are reachable by LANTA, WFMZ reported. In Philadelphia, Health Commissioner Palak Raval-Nelson declared a heat health emergency from July 1 through July 4, citing forecast heat index values approaching 110 degrees.
That week is also where the grid strain showed. PJM Interconnection, which runs the transmission system serving the Lehigh Valley, hit an estimated all-time peak of 168,158 MW between 5 and 6 p.m. July 2, passing the 165,563 MW record set Aug. 2, 2006. Forced generation outages ran between 18,100 and 19,400 MW over July 2-4, against the 12,800 MW average PJM cites for the top 10 summer peak days of the last three years.
PJM said it requested and received two Energy Department emergency orders, effective July 1 through July 6: one lifting environmental permit limits on generators, worth about 3.25 GW of output by PJM’s estimate, and one authorizing transmission owners to curtail data centers and other large loads with backup generation as a last resort. PJM warned large customers the evening of July 2 to be ready; the curtailment action itself, it said, was never needed and never issued.
What comes next is the El Nino now building. The Climate Prediction Center’s Aug. 13 discussion put the odds of a very strong event this fall and winter above 90 percent, with a 69 percent chance during October-December of an event stronger than any since 1950. The center’s next update is due today.