Oklahoma’s weather is driven largely by its topography. Elevations in the state range from less than 500 feet in the southeastern corner of the state to more than 4,000 feet in the far western Panhandle. Because of the general upward slope of the state, moisture tends to be more concentrated in the east, driving annual precipitation, temperature, and severe weather cycles.

Average temperature decreases across Oklahoma generally from the south to the northwest. Mean annual temperature along the Red River, Oklahoma’s southern boundary, is about 62 degrees and is about 58 degrees along its northern border with Kansas. Temperatures continue to decrease westward across the Oklahoma Panhandle to a state low of 56 degrees in the far west. Annual temperatures show a great variability in Oklahoma; almost everywhere has an annual temperature range of 100 degrees or more. For any place in the state, temperatures near 110 are common about two out of ten years, as are temperatures slightly below zero. State extreme temperatures range from 120 degrees (recorded six times) to 27 degrees below zero (twice). Most of the state has a growing season of more than 200 days, except in the western Panhandle where the growing season only lasts about 175 days.

Annual precipitation shows a strong east-to-west gradient across Oklahoma. Eastern portions of the state average up to 56 inches of precipitation annually, while portions of the Panhandle receive less than 17 inches, on average. The typical peak in precipitation comes in the spring for most of the state, except the Panhandle which has a summertime maximum. A secondary peak occurs during early autumn, and is especially pronounced in eastern Oklahoma. Measurable precipitation is recorded on about 45 days per year in Western Oklahoma to about 115 days near the Arkansas border. Most precipitation falls at night, while the maximum rainfall intensities are usually during late afternoon. The state records for annual precipitation are 84.47 inches, recorded in southeastern Oklahoma in 1957, and a meager 6.53 inches, recorded in the Panhandle the previous year. The state’s record for single-day rainfall is 15.68 inches, but unofficial total of over 20 inches have been recorded. Snowfall is frequent across northwestern Oklahoma, which averages nearly 30 inches of snow, but areas of southeastern Oklahoma may go several years between events. The state’s record snowfall is 87.3 inches, during the winter of 1911-1912. A more common threat to the state is ice. Two major ice storms struck Oklahoma during consecutive winters: December 2000 and January 2002, causing a combined $270 million in damages.

In addition to ice storms, the primary threats to safety and economy in Oklahoma are severe storms, floods, and droughts. Large and damaging tornadoes are a threat in almost any part of Oklahoma, but recent advances in technology and preparedness have reduced the loss of life. Oklahoma averages 54 tornadoes per year, 15 of them rating F2 or higher. Most tornadoes occur between late March and mid-June, although tornado outbreaks are sometimes associated with the secondary precipitation maximum in autumn.

Flood control projects stemmed many of the most devastating floods in the early 20^th century, but flash flooding remains a serious threat. Much of Oklahoma’s precipitation comes in the form of intense, but short-lived, convection, causing excessive runoff, especially in urban and suburban areas. While not a threat to life, drought can be devastating to Oklahoma’s economy. Precipitation variability is highest in the agricultural-intensive areas of the west, meaning droughts are a frequent nuisance. Droughts may last from several months to several years. Major drought episodes occurred from 1909-1918, 1930-1940, 1952-1958, and 1962-1972. Several recent years, beginning in the mid-1990s, have experienced short-duration but intense drought episodes.

This narrative was provided by the Oklahoma Climatological Survey.

Adapted from: Oklahoma’s Climate: An Overview, Oklahoma Climatological Survey

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