Pennsylvania Wildfire, Smoke, and Air Quality Map

Fire season and landscape

Most of the state's fire activity lands in a short spring window, roughly March to mid May, between snowmelt and leaf-out; November brings a smaller second season in dry years. Summers are usually quiet locally, but Canadian smoke has repeatedly pushed Pennsylvania's air quality to unhealthy levels in recent years, including the June 2023 episode that darkened skies statewide.

Public land makes up a major share of the state: the Allegheny National Forest in the northwest, more than two million acres of state forest across the ridges, and extensive state game lands in between. The terrain runs in long parallel ridges and valleys grading into plateau country, drained by the Susquehanna, Delaware, Allegheny, and Ohio. Flash flooding in steep hollows is a recurring hazard alongside spring fire.

• Red flag warnings in Pennsylvania cluster in April, when dry cold fronts cross cured oak litter, and the warning layer maps those days county by county.
• Ridge-top fires often show as satellite hotspots before any perimeter is published, so the 24-hour hotspot layer is the earlier signal in the state forests.
• When Canadian smoke crosses the Great Lakes, the smoke layer often shows it over the northwest corner of the state before it reaches Philadelphia's monitors.