It's Wednesday. RIP to the legendary Robert Redford, who died yesterday at the age of 89.

• Today's weather: High of 101 with a slight chance of thunderstorms tonight.

Today's newsletter is 887 words — a 3.5-minute read.

Summer temperatures are hanging around longer in the Valley and nationwide compared with in the early 1970s, a new analysis finds, as climate change affects all four seasons.

Why it matters: Temperatures staying high for longer periods can increase cooling demand (and cost) and prolong the risk of heat-related illnesses.

• Longer summers also elevate the risk of wildfires by drying out vegetation and soil, creating more fuel for blazes.

Zoom in: Summer temperatures are lasting an extra eight days on average in Phoenix compared to 1970, according to a new report from Climate Central, a climate research group.

• In Tucson, warm weather's sticking around an extra 24 days  — one of the most significant increases among U.S. cities.

How it works: Climate Central's analysis is based on NOAA data and reflects the last date each year with highs equal to or greater than historical summer-like temperatures.

• The group defined "summer-like temperatures" as the 75th percentile of daily highs during the 1991-2000 climate normal.

Flashback: Last year, extreme heat continued in the Valley into fall with the National Weather Service recording temperatures above 110° in October for the first time on record.

• Previously, the latest we'd ever seen 110° was Sept. 19, in 2010.

State of play: Summer-like temperatures aren't just lasting longer — they're getting hotter.

• So far, this September's temperatures are about a degree above average and each of the past three Septembers have seen above-average temperatures, NWS Phoenix meteorologist Katherine Berislavich told us.
• Last year, September temperatures were 5.4 degrees higher than average, she said.

By the numbers: Heat-related deaths in Maricopa County appear to be down this summer compared with last, though deaths are still trending much higher than a decade ago.

What's next: We are likely done with 110-degree days, but the Climate Prediction Center is still forecasting higher-than-normal temperatures in Phoenix for the weeks and months ahead, Berislavich said.

Go deeper

If it weren't for a sudden abundance of all things pumpkin spice, we might never know it's autumn here in the Valley.

State of play: While people in the rest of the country are preparing for colorful fall foliage and soup weather, Phoenix residents are still sweating through 100-degree days.

• If you want leaves that change color, you could always head to Flagstaff or other destinations in northern Arizona.