monthly climate summary

The dry weather that plagued Oklahoma through the final three months of 2017 showed no signs of letting up during the first month of 2018. The lack of precipitation was especially prominent across western Oklahoma where 19 of the Oklahoma Mesonet’s 120 stations received no precipitation for the month, and another 47 saw less than a quarter-inch. In some cases, the precipitation-free streak extended back to early October. The Mesonet sites at Woodward and Hooker had gone 113 consecutive days without a single drop of moisture by the end of January.

Oklahoma’s seemingly endless supply of mild weather came to an abrupt halt during the third week of December, ushering in a frigid end to a warm 2017. A bulge in the jet stream allowed frosty air to plunge southward and place most of the country into an arctic deep freeze. Oklahoma’s introduction to the cold air came on Dec. 21 and lasted through the end of the year. Highs in the 60s and even a few 70s were common during the first three weeks of December, topped by a high of 83 degrees at three Mesonet sites in southwest Oklahoma on the fourth.

Drought flourished across Oklahoma over the past month, fed by one of the state’s driest and warmest Novembers on record. Six of the Oklahoma Mesonet’s 120 stations recorded no precipitation for the month, and another 77 recorded a quarter of an inch or less. High temperatures rose into the 70s and 80s with regularity. The temperature at the Altus and Mangum Mesonet sites soared to 94 degrees on the 17th, the second highest November temperature on record in Oklahoma, dating back to 1892. It was also the highest temperature ever recorded in the state that late in the calendar year.

October’s weather was highly variable, and a bit too exciting at times as is usually the case during this transition period from summer to winter. Temperatures ranged from the teens to the 90s and rainfall totals fluctuated from double-digits to less than a quarter-inch. Flurries in the Panhandle as early as Oct. 11 brought the state its first snow of the season, although the sleds remained stored in the attic. The last of several cold fronts during the month provided trick-or-treaters with a chilly and sometimes damp search for candy.

Hot and dry weather dominated Oklahoma’s weather headlines for much of September, a drastic change from the extraordinarily mild and wet August the state had just experienced. Many wondered if fall’s premiere would wait until October, but those fears were soon alleviated with the arrival of a strong storm system during the month’s final week. High temperatures in the 50s and 60s along with generous rainfall amounts of 2-4 inches provided a pleasant burst of autumn for much of the state and a welcome bout of moisture for Oklahoma’s wheat farmers.

August is often Oklahoma’s most brutal summer month. The spring rains become a distant memory, heat gains momentum through July, and the state’s landscape turns a sickly shade of yellow. With drought intensifying along with the heat this summer, August looked bleak once again. However, Mother Nature was in a charitable mood. The upper-level heat dome – a common visitor to the Southern Plains in late summer – shifted to the west and brought Oklahoma under northwesterly flow aloft.

July followed Mother Nature’s customary script for mid-summer in Oklahoma, complete with long stretches of sun and scorching temperatures, wildly varying rainfall, and rapidly intensifying drought conditions. Rainfall fortunes were separated roughly between the haves to the southeast of I-44 and the have-nots to the northwest. Parts of the southeast saw more than 10 inches of rain, while less than an inch fell from central though west central Oklahoma. The precipitation extremes exemplified the moisture disparity within the state.

June, normally a pillar of Oklahoma’s spring rainy season, was very much a disappointment in that regard. Unfortunately, that lack of significant moisture fueled a quick return to drought across parts of the state. Central Oklahoma became particularly dry with deficits of more than 8 inches accumulating since the beginning of May. According to preliminary data from the Oklahoma Mesonet, the month finished with a statewide average of 2.97 inches, 1.55 inches below normal to rank as the 43rd driest June since records began in 1895.

May gets top billing as Oklahoma’s rowdiest weather month, and it certainly lived up to that notoriety this year. At least three major severe weather outbreaks occurred during May. These short but intense periods of disturbed weather brought the state tornadoes, severe winds, hail to the size of grapefruits, and widespread flooding. Data from the National Weather Service suggest as many as 50 tornadoes touched down during the month, a number that could rise as more possible twisters are investigated.

April took its penchant for widely varying weather to near satirical extremes across Oklahoma. Floods, tornadoes, drought and blizzards – Mother Nature pulled out all the stops to give Oklahoma nearly the entire gamut of weather hazards. As many as six separate storm systems traversed the state during April, but the worst was saved for last.  A powerful upper-level storm impacted the state from the 28th through the 30th. Widespread rainfall amounts of 3-6 inches produced flooding from southwestern through northeastern Oklahoma.