Historical weather data, all-time temperature records, and monthly climate averages for Johnstown, PA. Explore typical weather conditions by week for trip planning, and see how today compares to the historical record.
April 5th in Johnstown runs chilly, with average highs of just 55° and lows dipping to 30°. It's a coin-flip day for precipitation — 61% chance of rain — and a 15% shot at snow isn't off the table, as 1995 reminded everyone when temps bottomed out at 13°.
Johnstown's weather has real range: 127 degrees separate its all-time high of 99° (July 3, 1966) and its record low of -28° (January 21, 1994). Rainfall can be punishing too — 4.63 inches fell in a single day in July 1977, and 24 inches of snow buried the city on December 11, 1992.
Summer is Johnstown's sweet spot, peaking the week of July 16–22 with average highs of 82°, while mid-January bottoms out around 32°. June is the wettest stretch of the year, averaging 1.28 inches in a single week, so pack accordingly. Spring and fall offer mild shoulder seasons in the 60s, though expect volatility — especially in April.