Oklahoma Climate – Sep 2026September 2026 Update

Novarupta (Katmai) eruption

The largest volcanic eruption anywhere in the world in the 20th century - 13 km3 of magma, about thirty times the 1980 Mount St. Helens eruption - at Novarupta in Alaska on 6-8 June 1912. Ash reached 100,000 ft and cooled the Northern Hemisphere by roughly 0.3°C over 1912-13. Unlike a tropical eruption such as Pinatubo, a high-latitude eruption's haze stays in its own hemisphere, so it did little to the Southern Hemisphere.

Smithsonian Global Volcanism Program, Alaska Volcano Observatory, National Park Service, Oman et al. 2005

The Dust Bowl

The Oklahoma panhandle was the epicentre. Cimarron County lost topsoil on a scale that made farming impossible for years, and the exodus it triggered gave the country the word 'Okie'. Boise City is where a reporter, surveying the aftermath of the 14 April 1935 storm, coined the name 'Dust Bowl'.

Schubert et al. 2004, NCAR/UCAR

Black Sunday, the worst Dust Bowl storm

Black Sunday, 14 April 1935, began in the Oklahoma panhandle: a cold front drove a wall of dust south, turning a clear warm afternoon to complete darkness within minutes. It was the day after, reporting from Boise City, that Robert Geiger of the Associated Press first used the phrase 'Dust Bowl'.

NWS Norman

Post-WWII industrial expansion begins

After the Second World War, coal and oil use grew rapidly across Europe, North America and the Soviet Union. Global sulphur dioxide emissions rose from about 30 to about 130 million tonnes a year by 1980, and the sulphate haze they formed masked part of the greenhouse warming underneath - the effect known as 'global dimming'.

Klimont et al. 2013

The 1950s drought

Oklahoma's worst year of the 1950s drought was 1956 for rainfall, its driest in this site's 1950-2025 record (527 mm, 39% below its 1961-90 average) - and 1953 for heat, with 23.8 heatwave days, its 3rd-highest. Ranchers moved cattle north into Kansas to escape it, only for the drought to follow them there by 1953.

NOAA Drought.gov, NOAA Climate Program Office, Texas Water Development Board

Agung eruption

Agung's eruption in Bali put a veil of sulphate haze into the stratosphere that cooled global temperature by about 0.3°C over 1963-66.

Smithsonian Global Volcanism Program, NOAA Global Monitoring Laboratory

US Clean Air Act

The 1970 Clean Air Act set strict national standards for sulphur dioxide and particulates, and American skies got measurably cleaner over the decades that followed. There is a climate sting in that success: sulphate aerosols reflect sunlight, so removing them removed a cooling effect that had been partly masking greenhouse warming. Measured here, Oklahoma averaged +0.66°C warmer across 2006-2025 than across the two decades before the Act, 1951-1970, the smallest rise of the 49 states measured. That is not an absence of warming - every one of them is warmer than it was - but the southern Plains and mid-South warmed least of anywhere in the country over this period, a regional quirk researchers call the 'warming hole'. Oklahoma sits inside it.

US EPA

The 1973-74 La Niña

The strongest La Niña of the 1950-present record, part of a multi-year cool phase that also included a second, separate La Niña in 1975-76.

ONI -2.0°C · RONI -1.9°C

NOAA CPCENSO Tracker

The Mississippi flood of 1973

1973 was Oklahoma's 3rd-wettest year on record here - 1187 mm, +38% against its 1961-90 average.

USGS Professional Paper 937, NWS St. Louis

The cold winters of 1976-79

1979 is Oklahoma's coldest year in this site's 1950-2025 record. Its first months were the end of the winter of 1978-79, the coldest on record for the contiguous United States.

Illinois State Water Survey, Missouri Climate Center, Monthly Weather Review (1978), Wikipedia

Pacific Decadal Oscillation flips to a warm phase

The Pacific Decadal Oscillation is a North Pacific pattern, and its influence on this side of the country is weak and indirect - mostly through how it nudges the winter jet stream downstream. Its 1976-77 flip marks a genuine shift in Pacific-basin climate, but for eastern states the Atlantic Multidecadal Oscillation is the ocean cycle that matters more.

Learn more →

Global SO2 emissions peak

Global sulphur dioxide emissions peak at about 130 million tonnes a year, then begin a long decline as Europe, North America and Japan clean up their air. As the aerosol mask thins, the rate of global warming picks up through the 1980s.

Klimont et al. 2013

The 1980 heat wave and drought

1980 gave Oklahoma 20.9 heatwave days, its 5th-highest of the 1950-2025 record, alongside its 8th-driest year. Oklahoma sat under the same stubborn high-pressure ridge, which suppressed thunderstorm formation and so turned heat into drought.

NOAA NCEI Billion-Dollar Disasters, Linda Hall Library, Karl & Quayle 1981

El Chichón eruption

A sulphur-rich eruption in Mexico whose aerosol cloud stayed in the stratosphere for more than two years, cooling the Northern Hemisphere by about 0.2°C.

Smithsonian Global Volcanism Program

1982-83 El Niño

El Niño has only a weak pull on Oklahoma's winter rainfall - it is not one of the seven states where ENSO reliably moves it. In 1982-83 Oklahoma's winter rainfall ran +42% against the 1961-90 average, with temperatures +1.0°C. On NOAA's RONI index, which strips out background ocean warming, this is the strongest El Niño since 1950.

ONI +2.1°C · RONI +2.4°C

NOAA CPC, NOAA CPC (2)ENSO Tracker

Daytime warming catches up with the night-led pattern

Across 1961-90, 81% of the world's land saw nights warming faster than days. Across 1991-2020 the pattern reversed: 70% saw days warming faster, as the industrial haze that had been dimming daytime sunshine was cleaned up. The study compares two fixed thirty-year windows; measured as a turning point, this site's own global series turns around 1982.

Zhong et al. 2023

Mount Pinatubo erupts

Pinatubo's aerosol veil left a clear mark on Oklahoma. 1993, two years after the June 1991 eruption, is Oklahoma's 4th-coldest year of the 76 on record and no year since has been colder. A single large eruption can hold temperatures down for two or three years; it cannot reverse the trend.

Learn more →

Atlantic Multidecadal Oscillation flips to a warm phase

The Atlantic Multidecadal Oscillation flipped to a warm phase in 1995. It is an Atlantic cycle, but its reach is not confined to the coast: a warm AMO alongside a cool Pacific has been tied to more frequent drought across the western and central United States, including the widespread droughts of 1996 and 1999-2002. It is a natural cycle of roughly 60-70 years, so it shifts the baseline rather than driving the long-term trend.

Learn more →

1997-98 El Niño

In 1997-98 Oklahoma's winter rainfall ran +94% against the 1961-90 average, with temperatures +1.8°C - though ENSO's pull on rainfall here is weak. It is often treated as the textbook strong El Niño.

ONI +2.4°C · RONI +2.3°C

NOAA CPC, NOAA NCEIENSO Tracker

Pacific Decadal Oscillation flips back to a cool phase

The Pacific Decadal Oscillation returned to a cool phase around 1998-99. Its direct effects are western - drier conditions across the south-west, changes in North Pacific fisheries - and its influence on this side of the country is weak and indirect. The Atlantic Multidecadal Oscillation, which flipped warm in 1995, is the ocean cycle with more bearing on eastern weather.

Learn more →

1999 Bridge Creek-Moore tornado

Recorded the highest tornado wind speed ever measured (321mph via Doppler radar), the first billion-dollar tornado in US history, 36 deaths.

Wikipedia (NWS-sourced)

2006: a national heat record that lasted six years

2006 is Oklahoma's 5th-warmest year in this site's 1950-2025 record. It was the warmest year ever recorded for the contiguous United States at the time, beating the 1998 El Niño record - and it has since been pushed down to 10th nationally, passed by nine warmer years in under two decades.

NOAA NCEI, Science

Start of the sustained rise in US heatwave frequency

Oklahoma's own Heatwave Days (WSDI) count rose from a 1961-90 average of 3.3 days a year to 6.7 in 2016-25 - more than doubling, close to the 2.4x averaged across the 50 states.

World Bank CCKP (CCKP), NOAA Climate at a Glance

The 2012 drought and heat

Oklahoma recorded 24.2 heatwave days in 2012, its 2nd-highest on record here, alongside its warmest year on record and its 6th-driest year (653 mm).

NOAA NCEI, Summer 2012 Drought Update, NOAA NCEI, Drought

Post-2013 acceleration in US temperatures

4 of Oklahoma's ten warmest years on record have occurred since 2013 - fewer than in most states - but 7 of the ten have come since 2000, with 2012 the warmest of all. The acceleration is clear in Oklahoma's data; its year-to-year swings are simply wide enough to spread the warmest years further apart than the national mean does.

NOAA Climate at a Glance

2015-16 El Niño

In 2015-16 Oklahoma's winter rainfall ran +53% against the 1961-90 average, with temperatures +3.0°C - though ENSO's pull on rainfall here is weak. By the raw ONI index it was the strongest El Niño ever measured - a reminder that a strong index does not guarantee a strong local outcome.

ONI +2.6°C · RONI +2.3°C

NOAA CPCENSO Tracker

2015-2025: the eleven warmest years on record

Globally, the eleven warmest years on record have all happened since 2015. Oklahoma does not follow it: its hottest year is still 2012, the drought year. Five of its own eleven warmest fall in the 2015-2025 span, with 2012, 2011, 2006, 1998, 1956 and 1954 outside it. Oklahoma is one of 15 states where 2012 still tops the list.

Learn more →

The 2019 Arkansas River flood

Northern Oklahoma took 200-400% of its normal May rainfall in 2019, and that water went into the Arkansas River. 2019 finished as Oklahoma's 4th-wettest year in this site's 1950-2025 record, 33% above its 1961-90 average. The record flood crests happened downstream, in Arkansas.

NWS Little Rock, Encyclopedia of Arkansas

Low-sulphur shipping fuel rule (IMO 2020)

New international shipping rules cut the sulphur allowed in ship fuel from 3.5% to 0.5% almost overnight, removing about 8 million tonnes of sulphur dioxide a year. With less sulphate haze over the oceans, it may have added around 0.1°C of warming by 2023-24.

Gettelman et al. 2024

2023-24 El Niño

A strong El Niño arriving on top of long-term greenhouse warming, with the cut in shipping sulphur from the 2020 fuel rule adding a little more. Together they produced the record global temperatures of 2023 and 2024.

ONI +2.0°C · RONI +1.4°C

NOAA CPCENSO Tracker