Authorities believe a blistering heat wave that hit the Pacific Northwest earlier this week continued into Sunday has contributed to at least seven deaths, AP reports.

Driving the news: An elderly man living in Clackamas County, Oregon, was the latest suspected heat-related death. The man died in his home, which didn't have a functioning air conditioner, the county said in a statement.

• An excessive heat warning for a large swath of the Northwest is expected to persist through Sunday evening, per the National Weather Service. Excessive heat is also building in the Upper Midwest.
• Though the high temperatures have broke records, of particular concern has been the duration of the heat, as higher-than-usual low temperatures have meant that elderly and other vulnerable residents haven't felt the typical cooling overnight, per meteorologists in the NWS Seattle field office.

The big picture: Oregon's Eugene Airport has reached 100°F or more since July 25, tying for the second-most 100+ degree temperature readings ever in July, NWS Portland tweeted Saturday evening.

• Seattle broke 90°F again on Sunday, its sixth day in a row of 90°+ temperatures and a new record that make this heat wave the longest ever, formally eclipsing the hotter, deadlier one that hit last summer. Temperatures are expected to begin cooling on Monday.
• Much of the inland Northwest hit temperatures of 100°F or higher on Saturday and a similar forecast was expected Sunday, NWS Spokane tweeted Saturday.
• "Hot, dry and breezy conditions will lead to the potential for rapid fire spread today through Tuesday across the region," NWS Spokane tweeted Sunday, adding that a "fire weather watch" had been issued for Wenatchee Valley, Waterville Plateau and western Columbia Basin.

State of play: The heat and dry weather has also contributed to California's McKinney Fire, located near the Oregon border, which has become the state's biggest fire so far in 2022.

Our thought bubble, from Axios' Andrew Freedman: Human-caused climate change is leading to more frequent, severe and long-lasting heat waves around the world.

• Notable events that have broken all-time records so far this summer have hit the U.S., Europe and Asia. Extreme heat is likely to spread across the Lower 48 states again this week.

Editor's note: This article has been updated to include Seattle's heat wave record.