world heatwave 2018
© University of Maine Climate Reanalyzer
Simulation of maximum temperatures on July 3 from American (GFS) weather model at two meters above the ground.
(This article, originally published Tuesday, was updated Wednesday to add all-time heat records at Mount Washington, N.H., and Tbilisi, Georgia set since Monday. On Thursday, the story was updated to include information on heat-related deaths in Canada and extraordinary heat in Siberia. On Friday, it was updated to add the likely all-time heat record in Africa and Southern California.)

From the normally mild summer climes of Ireland, Scotland and Canada to the scorching Middle East to Southern California, numerous locations in the Northern Hemisphere have witnessed their hottest weather ever recorded over the past week.

Large areas of heat pressure or heat domes scattered around the hemisphere led to the sweltering temperatures. The Canadian Broadcasting Corporation reports the heat is to blame for at least 54 deaths in southern Quebec, mostly in and near Montreal, which endured record high temperatures.

In Northern Siberia, along the coast of the Arctic Ocean - where weather observations are scarce - model analyses showed temperatures soaring 40 degrees above normal on July 5, to over 90 degrees. "It is absolutely incredible and really one of the most intense heat events I've ever seen for so far north," wrote meteorologist Nick Humphrey, who offers more detail on this extraordinary high-latitude hot spell on his blog.

On Thursday, Africa likely witnessed its hottest temperature ever reliably measured. Ouargla, Algeria soared to 124.3 degrees (51.3 Celsius). If verified, it would surpass Africa's previous highest reliable temperature measurement of 123.3 degrees (50.7 Celsius) set July 13, 1961, in Morocco.

[Africa may have witnessed its all-time hottest temperature Thursday: 124 degrees in Algeria]

No single record, in isolation, can be attributed to global warming. But collectively, these heat records are consistent with the kind of extremes we expect to see increase in a warming world.


Let's take a tour around the world of the recent hot-weather milestones.

North America

A massive and intense heat dome has consumed the eastern two-thirds of the United States and southeast Canada since late last week. It's not only been hot but also exceptionally humid. Here are some of the notable all-time records set: [Oppressive heat dome engulfs the Northeast - and it will spread west this weekend]

Europe

Excessive heat torched the British Isles late last week. The stifling heat caused roads and roofs to buckle, the Weather Channel reported, and resulted in multiple all-time record highs:
  • In Scotland, Glasgow had its hottest day on record, hitting 89.4 degrees (31.9 Celsius). Previously, it was reported that Scotland set its hottest temperature on record of 91.8 degrees (33.2 Celsius) on June 28 in Motherwell, about 12 miles southeast of Glasgow. However, upon further evaluation, the U.K. Met Office determined the record was invalid due to an artificial heating source near the temperature sensor.
  • In Ireland, on June 28, Shannon hit 89.6 degrees (32 Celsius), its all-time record.
  • In Northern Ireland,
    • Belfast hit 85.1 degrees (29.5 Celsius) on June 28, its all-time record.
    • Castlederg hit 86.2 degrees (30.1 Celsius) on June 29, its all-time record.
Eurasia

A large dome of high pressure, or heat dome, has persistently sat on top of Eurasia over the past week, resulting in some extraordinarily hot weather: A GFS model shows a large upper-level high-pressure zone, or heat dome, over Eurasia on Monday. (TropicalTidBits.com) Middle East

As we reported, Quriyat, Oman, posted the world's hottest low temperature ever recorded on June 28: 109 degrees (42.6 Celsius).

1:55 How your body responds to hot temperatures

From your brain to your skin pores, this is what goes into your body keeping you cool when the heat turns up. (Claritza Jimenez/The Washington Post)

These various records add to a growing list of heat milestones set over the past 15 months that are part and parcel of a planet that is trending hotter as greenhouse gas concentrations increase because of human activity: