Under the Köppen climate classification, Davenport is considered to have a humid continental climate (Dfa). Summers are very warm to hot with high levels of humidity. Winters have cold temperatures and often high winds, with snow likely from November through February. Average snowfall in Davenport is 30.7 inches (780 mm) per year. January is on average the coldest month, while July is the warmest. The highest temperature recorded in Davenport was 111 °F (44 °C) on July 12, 1936. The lowest temperature, −29 °F (−34 °C), was recorded on January 18, 2009. Substantial weather changes frequently occur at three- to four-day intervals as a result of mid-latitude storm tracks, which is where low and high pressure extratropical disturbances occur.
Although several minor tornadoes have occurred, no devastating tornado has ever touched down in Davenport. Flooding, however, is often a problem in Davenport due to the lack of a flood wall. During the Great Flood of 1993, the water crested at 22.63 feet (6.90 m) on July 9. This is nearly 8 feet (2.4 m) above the 14.9-foot (4.5 m) flood stage. Major flooding in Davenport causes many problems. Roads in and around the downtown area, including U.S. Route 67, are closed and cause increased traffic on other city roads. The effects of major flooding can be long-lasting. For example, during the 2008 flooding, Credit Island in the city’s southwest corner remained closed for 5½ months while crews worked on cleaning up damage and removing river debris. Duck Creek, a stream situated in Bettendorf and Davenport, is also vulnerable to flash flooding. Severe thunderstorms on June 16, 1990, created heavy flash flooding in Bettendorf and Davenport that killed four people. Another major flood happened on June 12, 2008, when severe thunderstorms caused Duck Creek to overflow its banks and flood properties and nearby streets (see Iowa flood of 2008).