Climate in Pittsburgh

with a 24-hour average of 72.6 °F (22.6 °C). Conditions are often humid, and combined with highs reaching 90 °F (32 °C) on an average 9.5 days per annum, a considerable heat index arises. The coldest month is January, when the 24-hour average is 28.4 °F (−2.0 °C), and sub-zero lows (≤ −18 °C) can be expected on an average 2.6 nights per year. Extremes in temperature range from −22 °F (−30 °C), on January 19, 1994 to 103 °F (39 °C), which occurred three times, most recently on July 16, 1988.

Total precipitation is greatest in May and least in October, and the average annual precipitation is 38.1 inches (970 mm), yet, on average, December and January have the greatest number of days with precipitation. Snowfall averages 41.5 inches (105 cm) per season. In terms of cloudiness, there is an average of 59 clear days and 103 partly cloudy days per year, while 203 days are cloudy. In terms of annual percent-average possible sunshine received, Pittsburgh (45%) is similar to Seattle (43%).

Although Pittsburgh generally experiences moderate weather, a few extreme weather events occurred between 1990 and 2010. The 1993 Superstorm dropped 24" of snow on March 13 of that year, setting a daily snowfall record, and the First North American blizzard of 2010 (locally known as "Snowpocalypse" and "Snowmageddon") dropped 21" of snow in a 24-hour period during February 5–6 of that year. An F1 tornado entered city limits on June 2, 1998. On September 17, 2004, the remnants of Hurricane Ivan brought gusty winds and dropped 5.95" of rain, setting a daily rainfall record