Greensboro, like much of the southeastern United States, has a humid subtropical climate (Köppen Cfa), with four distinct seasons. Winters are short and generally cool, with a January daily average of 38.9 °F (3.8 °C). On average, there are 75 nights per year that drop to or below freezing,[a] and 4.3 days that fail to rise above freezing.[b] Measurable snowfall occurs nearly every winter, and accumulates to a normal of 7.5 inches (19.1 cm), usually in January and February and occasionally December and March; the actual amount may vary considerably from winter to winter.[c] Cold-air damming (CAD) can facilitate freezing rain, often making it a more pressing concern than snow. Summers are hot and humid, with a daily average in July of 78.5 °F (25.8 °C). There is an average 32 days per year with highs at or above 90 °F (32 °C), but, as in much of the Piedmont South, 100 °F (38 °C)+ readings are uncommon. Autumn is similar to spring in temperature but has fewer days of rainfall and less total rainfall. Extremes in temperature have ranged from −8 °F (−22 °C) on January 21, 1985, up to 104 °F (40 °C), on July 17, 1914.
Thunderstorms are common during the humid spring and summer months, some being severe. On April 2, 1936, at around 7:00 pm, a large, F-4 tornado cut a seven-mile (11 km) swath of destruction through southern Greensboro. 14 people were killed and 144 were injured from the tornado, which moved through part of downtown. The storm was part of an outbreak known as the 1936 Cordele-Greensboro tornado outbreak. Strong tornadoes have struck the Greensboro area since then, notably Stoneville on March 20, 1998; Clemmons and Winston-Salem on May 5, 1989; Clemmons and Greensboro on May 7, 2008; High Point on March 28, 2010; and Greensboro on April 15, 2018.