Cody experiences a semi-arid climate , with highly variable conditions. Relative humidity is usually a fairly dry 30% or less. Precipitation averages 10.5 inches or 266.7 millimetres annually, including 42.5 inches or 1.08 metres of snow per season. Due to the aridity, snow cover is highly unreliable, with 27 days per season with 1 inch or 0.025 metres or more on the ground. Cody enjoys about 300 days of sunshine per year.
Wind is almost a constant presence in the Cody area. Air flow in Cody area is turbulent, but during the winter most storms move in from the north-northwest. During the summer, it is not unusual to see storms move in from the southwest. Throughout a normal day, winds can be experienced as coming from almost any direction, mostly from the north and west, but sometimes from the south and east. The Canyon at the west end of Cody funnels rain and wind across the city from the west. The winds can be quite strong at 30 to 40 miles per hour (48 to 64 km/h) and last for several days.
Because of the dry climate, the entire area is laced with irrigation canals, holding ponds, laterals, and drops. The Buffalo Bill Dam between Rattlesnake and Cedar mountains forms a large reservoir about 10 miles (16 km) to the west of Cody. This reservoir (among others) feeds the Shoshone Project, a large irrigation water distribution system.
The monthly daily average temperature ranges from 25.9 °F or −3.4 °C in December to 69.9 °F or 21.1 °C in July. An average of 13.8 days have highs of 90 °F (32 °C) or higher and an average of 13.2 days have lows of 0 °F (−18 °C) or lower; the average window for freezing temperatures is September 27 thru May 14 and for measurable (≥0.1 inches or 0.25 centimetres snow, October 24 thru April 17. The record high temperature was 105 °F or 40.6 °C on July 14, 1925, and the record low temperature was −46 °F or −43.3 °C on February 8, 1936.
The wettest calendar year has been 1991 with 16.04 inches (407.4 mm) and the driest 1956 with 3.58 inches (90.9 mm). The most rainfall in one month was 5.76 in (146 mm) in June 1992. The most rainfall in 24 hours was 2.51 inches or 64 millimetres on July 22, 1973. There are an average of 70 days with measurable precipitation. The most snow in one year was 73.4 inches (1.86 m) between July 1916 and June 1917. The most snow in one month was 26.3 inches (0.67 m) in January 1972.