Las Vegas set a new record on Wednesday as it marked a fifth consecutive day over 115˚F (46˚C).
The brutal milestone marks yet another record for the Nevada desert city this week: on Sunday, Las Vegas hit an all-time high of 120˚F (48.8˚C). Even by desert standards, the prolonged baking the city is experiencing is nearly unprecedented.
In Oregon, the city of Portland saw record daily temperatures on Friday, Saturday and Sunday, and Salem set a new record, hitting 103˚F on Sunday.
Phoenix, Arizona, which has averaged the hottest temperature ever for the first eight days of July in records dating to 1885, tied the daily record on Tuesday of 116˚F (46.7˚C) set in 1958. Triple-digit temperatures were also recorded in Idaho.
Reno, Nevada, broke its daily record with 104˚F (40˚C) on Tuesday, and was suffering through the longest streak ever of days hitting 105˚F (40.6˚C) or higher. Before this week, the city – at an elevation of 4,500 ft (1,372 meters) – had never been that hot for more than two consecutive days in records dating to 1888.
The US heatwave comes as the global temperature in June set a record for the 13th straight month and marked the 12th straight month that the world was 1.5˚C (2.7˚F) warmer than pre-industrial times, the European climate service Copernicus said.
A new fire in Oregon, dubbed the Larch Creek fire, quickly grew to more than 5 sq miles (12 sq km).
In California, firefighters were battling least 18 wildfires, including a 42-sq-mile blaze. That blaze, called the Lake fire, was only 16% contained.
And north-east of Los Angeles, the 2-sq-mile Vista fire chewed through trees in the San Bernardino national forest and sent up a huge plume of smoke visible across the region.