Tornado lull, worsening drought define May

May brought an abrupt slowdown in tornado activity after a historic start to 2026. The year opened with January tying its monthly tornado record, followed by a record-setting March and an active April that pushed the preliminary annual count to 57 by the end of that month. May is normally Oklahoma’s most active tornado month, averaging 32.7 tornadoes since 2000, but the month produced only two official tornadoes, both on May 27 in southeastern Oklahoma. The record fewest for May is zero, set in 2005. Another possible tornado near Hobart remained under investigation.

Despite the relative tornado lull, May was far from uneventful. Large hail, damaging winds, summerlike heat and worsening drought all made their presence felt, while climatological spring — March through May — finished as the second-warmest on record. The month still managed one final brush with cold, however, with the season’s final freeze occurring May 7 at Kenton and four other Oklahoma Mesonet sites. The warmth extended beyond the season as well, with January through May also ranking as the second-warmest such period since records began in 1895. 

Dry May keeps drought entrenched

May continued the springtime dry spell across much of Oklahoma, with the statewide average rainfall total of 3.25 inches finishing 1.68 inches below normal and ranking as the 34th-driest May since records began in 1895. The deficits were most pronounced across western Oklahoma, where parts of the west-central region recorded less than 25% of normal rainfall for the month. Climatological spring — March through May — did little to help, finishing with 9.01 inches of rainfall statewide, 2.29 inches below normal and the 33rd-driest spring on record.

Drought coverage changed little during May, but drought intensity increased. The amount of the state in drought, defined as D1 to D4 on the U.S. Drought Monitor, remained nearly unchanged during the month, hovering around 81%. The more intense drought categories expanded, however, with severe-to-exceptional drought increasing from 44% to 47%, and extreme-to-exceptional drought rising from 30% to 37%. Exceptional drought (D4), the highest intensity on the Drought Monitor, also returned to Oklahoma for the first time since July 11, 2023, covering more than 4% of the state by the end of May. The result was a familiar split: some localized rainfall helped parts of the state, but persistent deficits kept drought entrenched across western Oklahoma and allowed the worst conditions to intensify.

May by the numbers

• Statewide average temperature: 69.4°F, 1.0°F above normal — the 42nd-warmest May since records began in 1895
• Temperature extremes: High of 107°F at Erick on May 15; low of 30°F at Kenton on May 7
• Temperatures of 100 degrees or above: 54 instances recorded at the 120 Oklahoma Mesonet sites
• Warmest and coolest locations: Highest monthly average, 73.2°F at Altus; lowest, 63.2°F at Kenton
• Statewide average precipitation: 3.25 inches, 1.68 inches below normal — the 34th-driest May since 1895
• Rainfall extremes: High of 8.62 inches at Tulsa; low of 0.63 inches at Camargo

Climatological spring by the numbers

• Statewide average temperature: 65.0°F, 5.3°F above normal — the second-warmest spring since records began in 1895
• Temperature extremes: High of 107°F at Erick on May 15; low of 5°F at Eva on March 16
• Statewide average precipitation: 9.01 inches, 2.29 inches below normal — the 33rd-driest spring since 1895
• Rainfall extremes: High of 17.5 inches at Tulsa; low of 1.2 inches at Arnett

Western drought relief possible in June

Drought improvement is possible across the western half of Oklahoma during June, according to the Climate Prediction Center’s outlook. The center’s temperature outlook indicates equal chances of above-, below- or near-normal temperatures statewide, while the precipitation outlook favors above-normal precipitation across much of western and north-central Oklahoma. That wetter signal could provide meaningful relief to some of the state’s hardest-hit drought areas. Farther east, however, drought is expected to persist or possibly intensify where it remains.