Youngstown has a humid continental climate , typical of the Midwest, with four distinct seasons, and lies in USDA hardiness zone 6a. Winters are cold and dry but typically bring a mix of rain, sleet, and snow with occasional heavy snowfall and icing. January is the coldest month with an average mean temperature of 25.8 °F (−3.4 °C), with temperatures on average dropping to or below 0 °F (−18 °C) on 4.1 days and staying at or below freezing on 43 days per year. Snowfall averages 62.7 inches (159 cm) per season, significantly less than the snowbelt areas closer to Lake Erie. The snowiest month on record was 53.1 inches (135 cm) in December 2010, while winter snowfall amounts have ranged from 118.7 in (301 cm) in 2010–11 to 25.2 in (64 cm) in 1948–49. Springs generally see a transition to fewer weather systems that produce heavier rainfall. Summers are typically very warm and humid with temperatures exceeding 90 °F (32 °C) on 7.7 days per year on average; the annual count has been as high as 40 days in 1943, while the most recent year to not reach that mark is 2014. July is the warmest month with an average mean temperature of 70.5 °F (21 °C).
The all-time record high temperature in Youngstown of 103 °F (39 °C) was established on July 10, 1936, which occurred during the Dust Bowl, and the all-time record low temperature of −22 °F (−30 °C) was set on January 19, 1994. The first and last freezes of the season on average fall on October 10 and May 6, respectively, allowing a growing season of 156 days; freezing temperatures have been observed in every month except July. The normal annual mean temperature is 49.0 °F (9.4 °C). Normal yearly precipitation based on the 30-year average from 1981–2010 is 38.91 inches (988 mm), falling on an average 160 days. Monthly precipitation has ranged from 10.66 in (271 mm) in June 1986 to 0.16 in (4.1 mm) in October 1924, while for annual precipitation the historical range is 54.01 in (1,372 mm) in 2011 to 23.79 in (604 mm) in 1963.