Bethlehem shares the Lehigh Valley's transitional climate, on the boundary between humid subtropical and humid continental zones. Sheltered between Blue Mountain to the north and South Mountain at its back, the city sees four full seasons without the extremes of the higher terrain on either side.
Summers are warm and humid, with July highs in the mid 80s and regular afternoon thunderstorms. Winters are cold but rarely severe — January lows average the low 20s and snowfall runs around 32 inches a year, much of it from coastal nor'easters that ride up the East Coast. Fittingly for the Christmas City, a white holiday season is a genuine coin flip rather than a guarantee.
The main hazards are summer thunderstorms, winter nor'easters and ice, and flash flooding along the Lehigh River and Monocacy Creek after heavy rain.
Climate normals (approximate)
- Warmest month: July — average high around 85 °F
- Coldest month: January — average low around 22 °F
- Annual precipitation: roughly 45 inches
- Annual snowfall: about 32 inches
- Climate type: humid subtropical / continental border
Common questions
- Does Bethlehem get white Christmases?
- Sometimes — snow on the ground on December 25 is roughly a one-in-four to one-in-three proposition. Most of the winter's snow arrives from January through early March.
- How much does it snow in Bethlehem?
- Around 32 inches a year on average, with coastal nor'easters responsible for the biggest single-storm totals in the Lehigh Valley.
- Is Bethlehem's weather different from Allentown's?
- Barely — both share the Lehigh Valley floor and the same reporting station (KABE). Differences show up mainly in hyper-local thunderstorm tracks and creek-level flash flooding.
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.