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May 2013 Global Weather Extremes Summary

By: Christopher C. Burt, 7:15 AM GMT on June 15, 2013

May 2013 Global Weather Extremes Summary

May was a very active month globally in so far as extreme weather events were concerned. Two violent EF-5 tornadoes (one on May 20th and the other on May 31st) raked the Oklahoma City area resulting in 45 deaths and billions of dollars in damage. A strong tornado also hit Modena, Italy. Record late season snowfalls and unusual cold affected portions of the central and eastern U.S. while extreme heat prevailed in India and Southeast Asia as well as eastern and northern Europe. Near record cold was experienced in Alaska, and portions of Western Europe (along with unseasonal snow) and Iceland.

Below is a summary some of the month’s highlights.


Violent EF-5 rated tornadoes struck the Oklahoma City not once but twice during the month. The Moore tornado on May 20th was particularly devastating as it sliced through the densely populated Oklahoma City suburb of Moore killing 24 and causing approximately $1.5-2 billion in damage. Eleven days later the southwestern suburb of El Reno was struck by yet another EF-5 tornado and flooding rains which resulted in an additional 21 deaths including three well-respected storm chasers. The El Reno tornado was also one of the widest on record in the world being 2.6 miles wide at one point. Severe storms in Kansas resulted in hail up to 5.25” (13.3 cm) in diameter to fall in Montrose, Kansas.

The El Reno EF-5 rated tornado killed veteran storm chaser/tornado researcher Tim Samaras, his son Paul, and colleague Carl Young while ‘chasing’ the El Reno twister. The reason they died is because the storm made a very unusual turn to the northeast as it coursed across the Oklahoma suburbs. The chasers, who were in the path of the storm as it was heading in a southeasterly direction made the logical choice of driving north to avoid the tornado’s progression. Incredibly, the tornado made an unusual turn to the northeast and intercepted the crew. I would say it is almost unprecedented that a large and violent tornado would follow such a path. This map illustrates that path. Map from NWS.

There were two freak late-season heavy snowfalls during May in the U.S. The first affected a large portion of the Midwest from Arkansas to Wisconsin on May 1-3 with as much as 21” (53 cm) falling in northwestern Wisconsin and 14” (36 cm) in Rochester, Minnesota. It was Rochester’s (no stranger to heavy snowfall) 4th greatest snowstorm on record (for any month)! Arkansas reported measurable snowfall for the first time in recorded history.

Owatonna, Minnesota picked up 18” (46 cm) of snow during the May 1-3 snow event. This snowstorm was virtually unprecedented (I’m using that word a lot in this blog) for much of the Midwest. For details about the storm see my blog on the subject posted May 4th.

Late in the month, May 25-26, exceptional snowfall fell at the higher elevations of upstate New York and Vermont. Whiteface Mountain, New York reported an astonishing 36” (91 cm) accumulation, probably the deepest snowfall ever recorded so late in the season for anywhere in New York or New England. Yet another unprecedented extreme weather event. See my earlier blog for details. Gander, Newfoundland in Canada saw an amazing snowfall of 69 cm (27.2”) on May 19th.

The month was generally a wet one for the U.S. and the wettest May on record for Iowa. For the most part the rains were beneficial, alleviating drought concerns for portions of the northern and eastern Plains. But some rainfalls were so extreme as to cause major flooding, such as the 12.20” (310 mm) 24-hour rainfall in San Antonio, Texas on May 24-25. This was the city’s 2nd greatest 24-hour rainfall on record. For this and other flood events in the U.S. during May see a blog I posted on the subject earlier.

Temperatures in the Plains were like a roller coaster with daily record lows followed by daily record highs (and visa-versa) just days apart. Amarillo, Texas went from 97°F (36.1°C) on the afternoon of April 30th to 36°F (2.2°C) and snowing just 10 hours later early in the morning of May 1st. See my earlier blog on these temperature swings for more details. The temperature peaked at 108°F (42.2°C) in Nebraska on May 14th following freezing temperatures just a couple of days earlier. However, the Southwest and California continued to see extreme drought conditions persist. An ominous fire season is developing with a very large fire near Camarillo in southern California erupting on May 2nd. Large and dangerous wildfires this early in the season are unprecedented in the state history. Needless to say, as June progresses, the situation is deteriorating with Colorado now experiencing its most destructive wildfire in history (more about that in the June summary).

A large wildfire burned 27,000 acres (43 square miles) near Camarillo, California in early May. California has never seen so many wildfires develop so early in the season before. It has been the driest January 1-June 1 period on record for many areas including San Francisco which has precipitation records dating back to 1849. Photograph from wunderground.com.

The month was unusually cold (at least for the first three weeks) in Alaska. Fairbanks shivered through its coldest April 15-May 15th period on record. A rapid warm up the last week of May prevented the site from breaking its coldest May of record. Temperatures fell as low as -25°F (-31.7°C) at Deadhorse (Prudoe Bay) on May 1st. This was just one degree short of the Alaska state record for May and the -12°F (-24.4°C) on May 19th at Deadhorse was the coldest temperature ever measured so late in the season in state weather history. Unusual cold also persisted in the Southeast of the contiguous U.S. with several states reporting their top ten coldest Mays on record.

Maps of May temperature and precipitation rankings in relation to the NCDC 119 period of record for such. It was not just Iowa’s wettest May on record but also their wettest spring (March-May) as well. NESDIS/NOAA

In the Eastern Pacific Hurricane Barbara made landfall in southwestern Mexico on May 29th bringing heavy rains but causing relatively little damage. At least two deaths were attributed to the storm. It was the 2nd earliest hurricane to make landfall in Mexico on record.

The coldest temperature measured in the northern hemisphere during May was -39.3°C (-38.7°F) at Summit, Greenland on May 6th.


The warmest temperature measured in the southern Hemisphere during May was a reading of 40.1°C (104.2°F) at Villamontes, Bolivia on May 28th. This was the latest 40°C (104°F) reading reliably measured anywhere in the southern hemisphere! (Australia’s record May temperature is 40.6°C/105.1°F set at Bidyadanga, Western Australia on May 6, 1990 but it has never seen a 40°C temperature after May 6th).


It was the coldest May since 1996 in the U.K. with even a few locations in Dartmoor and Shopshire reporting measurable snow on May 15th. It has been the coldest spring (March-May) since 1962. The highest temperature reported during the month was 23.8°C (74.8°F) at Drumburgh, Cumbria on May 7th and the coldest -5.5°C (22.1°F) at Alston, Cumbria on May 2nd. The heaviest 24-hour rainfall reported was 72.0 mm (2.83”) at Pembrey Sands, Carmarthenshire on May 14-15. This storm also brought wind gusts of 74 mph to the Isle of Wight (at Needles Old Battery).

Elsewhere in Europe it was an upside down month temperature-wise with incredible warmth in northern Scandinavia and unusual cold in Spain. Eastern Europe and the Balkans experienced a couple of strong heat waves. Moscow reached a very unseasonable 30°C (86°F) on May 10th, the warmest ever recorded there so early in the season. A very unusual configuration of the jet stream brought astonishing temperatures to Finland, northern Sweden and Norway the last days of May (and flooding rains to Germany and Austria—to be covered in June summary—but see Jeff Master’s blog on the subject. Tanabru, Norway located above the 70° latitude, measured 30.6°C (87.1°F) on May 31st. In Finland 30.5°C (86.9°F) was achieved at Kevo, and Sweden saw 30.2°C (86.4°F) at Markunsvinsa. These are readings rarely seen in mid-July let alone May for areas so far north in the region. Meanwhile, snow was reported as low as 1000 meters (3900’) in northern Spain on May 17-18 and it even snowed at low elevations in Belgium (at Spa) as late as May 23rd. Exceptional cold also affected Iceland during the month with a national May record of -21.7°C (-6.9°F) reported at a station called Bruarjokull B10 on May 2nd.

A rare strong tornado and large hail swept through Modena, Italy on May 3rd. There were at least 11 injuries and considerable property damage reported.

An impressive and rare strong tornado struck Modena, Italy on May 3rd injuring 11 and damaging several structures. Photographer not identified.


Extreme heat in Northern Africa brought some of the highest temperatures ever reliably measured to Libya (49.9°C/121.8°F) at Marada on May 28th and Egypt (49.0°C/120.2°F) at Kharga on May 31st. Contrary to popular belief, temperature above 120°F are relatively rare in the Sahara Desert.


Flash floods in central Saudi Arabia resulted in 16 deaths on May 1st and three more in Oman. It was said to have been the heaviest rainfall reported anywhere in the kingdom for 25 years. Bisha (Bishah), which is about 200 miles southeast of Jeddah, measured 143.3 mm (5.64”) in a 24-hour period May 1-2. This is about what the average annual precipitation would be for this location. On a historical note, a flash flood in Jeddah, Saudi Arabia resulted in 123 fatalities in 2009.

The deadliest flood in Saudi Arabia since 2009 has washed out desert highways and drowned at least 16. The 143.3 mm (5.64”) of rain in Bisha was said to have been the heaviest rainfall observed anywhere in the country for 25 years. Heavy rains in Oman resulted in the deaths of an additional three. Photo from Arabnews.com

Cyclone Mahasen formed in the Bay of Bengal and threatened Bangladesh and Myanmar (Burma) in mid-May. Fortunately the storm weakened prior to landfall and caused little damage.

May is usually the hottest month of the year for northern India and Pakistan and this May was no exception. The hottest temperature measured in the world this past month was 51.0°C (123.8°F) at Larkana, Pakistan on May 18th. Amritsar, the capital of Punjab Province in India, saw the temperature reach 48.0°C (118.4°F) on May 23rd and May 24th. This was the hottest ever recorded there and is particularly impressive given that weather records date back to 1880 in Amritsar. Another all-time heat record was broken at Nagpur Sonegaon Airport, India on May 22nd when the temperature soared to 47.9°C (118.2°F). Oppressive heat was felt in Southeast Asia as well with Bangkok’s Don Muang Airport registering its hottest May on record with an average monthly temperature of 31.9°C (89.4°F). Former record was 31.7°C (89.1°F) in May 1997. Downtown Bangkok was even toastier with the Klong Thoey site averaging 32.3°C (90.1°F). The humidity was (as usual) very high with one day seeing a heat index temperature reaching 72°C (161.6°F) according to resident and climate scientist Maximiliano Herrera. Hanoi, Vietnam hit 40.0°C (104°F) on May 16th, just 0.1°C shy of their all-time heat record.


South Australia reported its 4th warmest May (with warmest average minima) on record. It was the 9th warmest May for Australia as a whole. It was also a wet month, ranking as the wettest May since 1997 (out of 114 years of record).

May deciles for average maximum temperature (top) and precipitation (bottom). Maps courtesy of the Australian Bureau of Meteorology.

The highest temperature measured during the month was 39.2°C (102.6°F) at Mandora, West Australia on May 6th and the coldest -8.8°C (16.2°F) at Cooma Airport, New South Wales on May 25th. The greatest calendar day rainfall was 236 mm (9.29”) at Daradgee, Queensland on May 9th.


After the drought earlier this year, there has been an abrupt turnaround precipitation-wise. Auckland Airport (POR begins in 1959) reported its wettest May on record with a 261 mm (10.28”) total. This was 242% of normal. The greatest calendar rainfall during the month was 124 mm (4.88”) at soggy but beautiful Milford Sound, South Island on May 31st. The warmest temperature measured in New Zealand during May was 25.3°C (77.5°F) at Leigh, North Island on May 3rd and the coldest -7.1°C (19.2°F) at Motu, North Island on May 29th.


The coldest temperature in the southern hemisphere and the world during May was -78.3°C (-108.9°F) recorded at Dome Fuji on May 22nd.

P.S.: Photo of the Month

A bonus photo, my pick for the most amazing photograph of the month (perhaps one of the most special atmospheric-related pics ever), taken by Mike Hollingshead on May 31st near Denison, Iowa. It features not only a (distant) thunderstorm AND an aurora but ALSO (most incredibly) some red sprites squirting into the atmosphere above the structure on the left. Sprites are an elusive phenomenon and very rarely observed from the surface of the earth (normally only seen by air and spacecraft). You can see and read more about this on Hollingshead’s web site here.

Thunderstorms, auroras, and sprites all in one shot. Hey, where's the rainbow? Photo by Mike Hollingshead.

Christopher C. Burt
Weather Historian

KUDOS Thanks to Maximiliano Herrera for global temperature extremes and Jeremy Budd and NIWA for the New Zealand extremes.

Extreme Weather

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

Reader Comments

Much of the extreme weather in the northern hemisphere, and especially in the US and western Europe has been linked to the "unwinding" of the polar vortex, which when normally "tight" entrains the cold Arctic air masses closer to the polar region. Arctic ice loss and more open water seasonally has shifted the whole energy dynamic in the Arctic, reducing albedo, increasing water vapor, etc. What has been happening, I understand is both a "slumping" of Arctic air masses toward lower latitudes, and an associated shifting of the jet stream into sometimes wild meanders that shift air masses around in peculiar ways. So you have very cold air masses dipping down toward the center of the US, for example, which meet warm moist masses coming up from the Gulf or in from the west... helping to generate powerful storms. A meander that curled first up past Iceland, then downward and east again helped give western Europe some of its nastiest winter weather in decades recently.
Anyway I think the loss of Arctic ice can be viewed as an ideal "poster child" for global warming. It also answers the question:"if it's global warming, why are we getting record cold temperatures and lots of snow??"
Hard to believe that a month that started out with record cold and may snow in some areas finished with some of the most violent tornadoes ever recorded, with record heat and flooding in between! If this is going to get crazier due to the effects of our pollution, it will be a very interesting future. Here in nyc, june is turning out to be very pleasant as far as temperatures go, but we may break the record monthly rainfall in a few days.
Thanks for the blog! Great roundup.
I agree on the picture, almost otherworldly. The 161 degree heat index equally impressive. Is this approaching a record? Curious as to the conditions that generated this figure.
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