Harrisburg lies in the broad Susquehanna Valley, on the boundary between humid continental and humid subtropical climates. Sheltered to the west by the Appalachian ridges, the capital sees warm, humid summers and cold winters, with all four seasons clearly defined.
Summers are warm and sticky — July highs around the upper 80s with afternoon thunderstorms. Winters are cold, with January lows in the mid 20s and roughly 28 to 30 inches of snow a year, a mix of clippers and the occasional coastal storm. Precipitation runs around 41 inches annually and is spread fairly evenly.
The defining hazard here is the Susquehanna River, one of the most flood-prone major rivers in the country. Tropical Storm Agnes in 1972 and Tropical Storm Lee in 2011 both caused catastrophic flooding in the Harrisburg area, and ice jams and spring snowmelt remain annual concerns along the river and its creeks.
Climate normals (approximate)
- Warmest month: July — average high around 88 °F
- Coldest month: January — average low around 24 °F
- Annual precipitation: roughly 41 inches
- Annual snowfall: about 28–30 inches
- Climate type: humid continental / subtropical border
Common questions
- Does Harrisburg flood?
- Yes — the Susquehanna River is highly flood-prone. Tropical Storm Agnes (1972) and Tropical Storm Lee (2011) brought major flooding, and ice jams and snowmelt are recurring spring risks.
- How much snow does Harrisburg get?
- Roughly 28 to 30 inches a year on average, mostly from December through March, from a mix of fast-moving clippers and occasional coastal storms.
- How humid are Harrisburg summers?
- Quite humid. July highs reach the upper 80s and muggy afternoons frequently fire off thunderstorms across the valley.
Figures are long-term climate normals (roughly the 1991–2020 reference period) and are meant for context. The live readings at the top of this page always reflect current conditions.