Kansas City lies in the Midwestern United States, near the geographic center of the country, at the confluence of the Missouri and Kansas rivers. The city lies in the northern periphery of the humid subtropical zone, but is interchangeable with the humid continental climate due to roughly 104 air frosts on average per annum. The city is part of USDA plant hardiness zones 5b and 6a. In the center of North America, far removed from a significant body of water, there is significant potential for extreme hot and cold swings throughout the year. The warmest month is July, with a 24-hour average temperature of 81.0 °F (27.2 °C). The summer months are hot and humid, with moist air riding up from the Gulf of Mexico, and high temperatures surpass 100 °F (38 °C) on 5.6 days of the year, and 90 °F (32 °C) on 47 days. The coldest month of the year is January, with an average temperature of 31.0 °F (−0.6 °C). Winters are cold, with 22 days where the high temperature is at or below 32 °F (0 °C) and 2.5 nights with a low at or below 0 °F (−18 °C). The official record highest temperature is 113 °F (45 °C), set on August 14, 1936, at Downtown Airport, while the official record lowest is −23 °F (−31 °C), set on December 22 and 23, 1989. Normal seasonal snowfall is 13.4 inches (34 cm) at Downtown Airport and 18.8 in (48 cm) at Kansas City International Airport. The average window for freezing temperatures is October 31 to April 4, while for measurable (0.1 in or 0.25 cm) snowfall, it is November 27 to March 16 as measured at Kansas City International Airport. Precipitation, both in frequency and total accumulation, shows a marked uptick in late spring and summer.
Kansas City is located in “Tornado Alley”, a broad region where cold air from Canada collides with warm air from the Gulf of Mexico, leading to the formation of powerful storms, especially during the spring. The Kansas City metropolitan area has experienced several significant outbreaks of tornadoes in the past, including the Ruskin Heights tornado in 1957 and the May 2003 tornado outbreak sequence. The region can also experience ice storms during the winter months, such as the 2002 ice storm during which hundreds of thousands of residents lost power for days and (in some cases) weeks. Kansas City and its outlying areas are also subject to flooding, including the Great Floods of 1951 and 1993.