Pittsburgh, PA – Residents in western Pennsylvania are experiencing a historic weather milestone this September, as the National Weather Service (NWS) reports record-cold overnight temperatures over the past three weeks.
According to the U.S. National Weather Service Pittsburgh, temperatures between August 25 and September 14 ranked as the coldest late-summer overnight lows in 155 years of recordkeeping. Meteorologists attribute this trend to recent cloud-free nights combined with wide day-to-night temperature swings.
For the year to date, Pittsburgh has averaged 65.4°F, which is 1.5 degrees warmer than normal. Daytime highs have been slightly above average, but the cooler nighttime conditions pushed recent lows well below typical September levels.
Precipitation for 2025 is also tracking lower than usual. The region has received 25.83 inches of rain so far, about 3.5 inches below normal, making it the 50th driest year on record. Still, rainfall totals remain far from historic lows, with occasional wetter-than-average weeks balancing extended dry stretches.
The data reflects broader seasonal variability, with Pittsburgh ranking as the 27th warmest overall year to date, but simultaneously recording one of the sharpest late-summer cold snaps on record.
Officials note that the unusual conditions may continue to affect agriculture, outdoor activities, and energy use as the region transitions into fall.
