SAN FRANCISCO (CBS SF) — July temperatures soared to an average all-time high in California, fueling a historic outbreak of deadly wildfires and scorching record heat in Death Valley, the National Weather Service announced Wednesday.

The weather service said July’s 79.7°F mean temp was an all-time high for any month and was five degrees above the 20th century average.

Death Valley set a new tentative world’s record for hottest month anywhere on Earth. The monthly average was a scorching 108.1 degrees Fahrenheit.

The daily high was 127 degrees Fahrenheit four days in a row in July, the National Park Service said. And sunset didn’t bring much relief. Temperatures failed to drop below 100 for 10 nights in the month — with the lows not coming until usually around 5 a.m., just before sunrise.

The previous record was set last July with 107.4 in Death Valley, said Andy Gorelow of the National Weather Service’s Las Vegas office.

To reach the average heat measurement, meteorologists first average each day’s temperature from its high and low, and then average each day’s average, said Brian Brettschneider, a climate scientist who conducts research for the University of Alaska Fairbanks at the International Arctic Research Center. He kept an eye on Death Valley’s readouts after last year’s chart-topping July.

The searing heat has created a weather nightmare for firefighters. The record temperatures, single digit humidity, tinder-dry brush and winds have combined to fuel a historic and destructive outbreak of wildfires across the state.

Currently, there are two wildfires burning that have charred more than 100,000 acres each. The Mendocino Complex Fire has become the largest wildfire in California history, growing 251,166 acres early Wednesday. It was 46 percent contained and had destroyed 116 homes and damaged 12 others.

The Carr Fire has charred 173,522 acres and was 47 percent contained early Wednesday. It has claimed six lives and destroyed 1,072 homes.

Lastly, the Ferguson Fire continued to force the closure of many areas of the Yosemite National Forest. By Wednesday morning it had grown to 94,972 acres and was 43 percent contained.

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