Denver Weather
Denver has a semi-arid climate with four distinct seasons. 
While Denver is located on the Great Plains, the weather of the city and surrounding area is heavily influenced by the proximity of the Rocky Mountains to the west. The climate is considered a high-desert climate. While generally mild compared to the mountains to the west and the plains further east, it can be very unpredictable. Before the city’s settlement, the Denver landscape was made up of primarily prairie and desert lands. Because Denver and most of its suburbs sit in a “bowl”, the city is often protected from harsh cold and strong winds. Measurable amounts of snow have fallen in the Denver area as late as June and as early as September.
The average temperature in Denver is 50.1 °F, and the average yearly precipitation is 15.81 inches. The season’s first snowfall generally occurs around October 19, and the last snowfall is about April 27, averaging 61.4 inches of seasonal accumulation. The National Weather Service records an annual average of sunshine during 69 percent of all possible daylight hours.
Denver’s winters can vary from mild to cold, and although large amounts of snow can fall on the mountains just west of the city, the effects of orographic lift dry out the air passing over the Front Range, shielding the city from precipitation for much of the season. Additionally, warm chinook winds occasionally occur as air passing over the mountains heats as it descends, quickly melting snow accumulations and making Denver’s winters milder than areas without this effect. The coldest temperature ever recorded in Denver was recorded on January 9, 1875 at -39 °F, and the last time Denver recorded a temperature below -20 °F was during February 2007, when the low temperature was -22 °F.
Spring brings with it significant changes as Denver can be affected by air masses on all sides. Arctic air from the north can often combine with Pacific storm fronts bringing snow to the city. In fact, March is Denver’s snowiest month, averaging 11.7 inches of snow. Additionally, warm air from the Gulf of Mexico can bring the first thunderstorms of the season, and continental warm air can bring summer-like warm and dry conditions.
Starting in mid-July, the monsoon brings tropical moisture into the city and with it come frequent short (and occasionally severe) late-afternoon thunderstorms. However, despite this tropical moisture, humidity levels during the day generally remain low. The average high during the summer is 88 °F and the average low is 59 °F. The hottest temperature ever recorded in Denver is 105°F (National Weather Service).
In the autumn, the tropical monsoon flow dies down and as Arctic air begins to approach, it can combine with moisture from the Pacific Northwest to bring significant snowfall to the city – November is Denver’s second snowiest month, and Denver’s greatest recorded snowfall from a single storm, 45.7 inches, fell in late autumn from December 1 to December 6, 1913.