Why Your Electric Car Loses Range in a Heat Wave, Too

Ask an EV owner about range anxiety and most will mention January, not July. Winter’s toll on batteries gets rehashed every cold snap, practically as a seasonal ritual. Summer’s version barely registers by comparison — less because it’s trivial and more because almost nobody tested it rigorously across a full spread of temperatures until fairly recently. Fresh data finally closes that gap.

Spring 2026, By the Numbers

This spring, engineers at AAA, teamed up once more with the Automobile Club of Southern California’s research arm, put six 2025-and-2026-model vehicles through a climate-controlled test cell: three battery-electric models — a Chevrolet Equinox EV, Ford Mustang Mach-E, and Tesla Model Y — plus three hybrids, a Toyota Prius, Honda CR-V, and Hyundai Tucson. Compared with a 75-degree control run, pushing the chamber to 95 degrees trimmed the electric trio’s overall efficiency by 10.4 percent and cut their range by 8.5 percent. Hybrids took an even bigger efficiency hit at that temperature, losing 12 percent, because their gas engines and battery packs both had to pitch in on keeping cabin and battery cool, Auto123 reported after digging into the same dataset.

Winter remains the tougher season by far. Dropping the chamber to 20 degrees erased 39 percent of the EVs’ range and roughly 23 percent of the hybrids’ fuel economy — figures that AAA’s Greg Brannon told NPR haven’t moved much in years: “the electric vehicles actually didn’t change all that much from back in 2019.”

A Partial Fix, Seven Years Later

That earlier round of testing — conducted in February 2019 — evaluated five EVs and no hybrids at all: a BMW i3, Chevrolet Bolt, Nissan Leaf, Tesla Model S, and Volkswagen e-Golf. Flipping on the AC once the chamber hit 95 back then cost drivers 17 percent of range — exactly double what AAA measured this year — while heating the cabin at 20 degrees sliced off 41 percent, just two points worse than this spring’s 39 percent result. Brannon told reporters covering that original study that “the impact of temperature on EVs is significantly more than we expected.”

AAA is careful not to present this as a clean before-and-after, however. Since the two rounds of testing sampled entirely different vehicles nearly a decade apart, the organization has acknowledged that any tidy read of “improvement” comes with real caveats. Even so, the pattern tracks with what engineers would predict: manufacturers have spent years refining heat pumps and cabin cooling — a comparatively solvable problem — while pulling heat out of nothing in freezing conditions remains a tougher physics challenge that hasn’t budged nearly as much.

What Actual Drivers Are Reporting

Laboratory chambers only capture part of the picture. Recurrent, a firm that pulls live battery data from a large, growing fleet of EVs, has been tracking summer performance independently. Its latest analysis, covering nearly 30,000 vehicles, found that range barely moves at 90 degrees, averaging around 5 percent — though EVs with heat pumps tend to lose a bit more, around 7 percent, than those without, closer to 3 percent — before climbing into the 17-to-18 percent range once temperatures hit 100 degrees.

That’s notably gentler than a prior Recurrent study built on a much smaller sample of 7,500 vehicles, which had estimated worst-case losses climbing above 31 percent. Recurrent itself flagged that older figure as resting on thin data, and the gap between the two rounds of research looks more like a function of sample size than any real shift in how EVs handle heat.

Not Every EV Handles Heat the Same Way

Averages also mask real spread between individual models. EV Engineering & Infrastructure, citing Recurrent’s tracking, reports a Ford F-150 Lightning shrugging off 90-degree heat with barely a 1 percent range loss, while a Nissan Leaf — long reliant on simpler, passive cooling instead of an active thermal system — gives up closer to 22 percent under identical conditions. AAA’s own spring results echoed that pattern: of its three EVs, the Mustang Mach-E held up best in the heat, shedding only 3 percent of range at 95 degrees, while the Tesla Model Y in that same lineup dropped more than 21 percent — proof a heat pump alone doesn’t guarantee an easy summer. Tesla’s heat-pump-based climate system remains notably efficient on its own terms, typically consuming between 1 and 3 kilowatts to keep the interior comfortable and occasionally spiking as high as 6, per Recurrent’s tracking — though the Model Y’s glass roof keeps resurfacing as a complicating factor elsewhere in this story.

It Might Not Be the AC At All

Something else can overwhelm air conditioning’s effect once a car actually gets moving: plain aerodynamics. Geotab, drawing on upward of 3 million commercial-fleet trips, found that a 65-kilowatt-hour electric cargo van cruising through 86-degree heat saw its range drop from 143 miles at 50 mph to just 88 miles at 80 mph — a bigger hit than air conditioning by itself usually causes. Electric sedans in the same dataset showed a smaller but similar pattern. As Geotab’s Charlotte Argue put it, “your right foot can make the biggest difference,” particularly once speeds climb into highway territory.

Blame the Equipment, Not Just the Weather

Part of why cold weather dominates this conversation while extreme heat gets treated as a footnote comes down to hardware limits, not relative importance. The rolling-road setup AAA relies on for this testing sits inside a chamber that tops out at 95 degrees Fahrenheit and bottoms out at 20. That means the most widely cited laboratory benchmark simply can’t reach the triple-digit afternoons now ordinary across Arizona, California’s Central Valley, or southern Spain each summer.

When the British publication What Car? drove three EVs — a Citroën e-C3, Kia EV3, and Tesla Model 3 — across southern Spain in temperatures between 104 and 111 degrees, InsideEVs reported that all three landed well short of their official range ratings, with shortfalls stretching from roughly 29 percent up to 44 percent. Worth noting: that gap reflects sustained highway speeds as much as the heat itself, not temperature in isolation — a reminder of how much a heavy right foot matters, per the point above. Even so, the Tesla came out worst of the trio, a result the outlet tied partly to its glass roof forcing harder use of the air conditioning.

The Basic Physics Behind the Numbers

None of this happens by accident. A gasoline engine throws off enormous waste heat, more than enough to warm a cabin at no real cost. Electric motors don’t generate nearly as much surplus heat, so keeping the interior comfortable — and keeping the pack itself somewhere in the 68-to-77-degree range where lithium-ion chemistry performs best — has to come from the very same battery driving the wheels forward.

Small Habits That Actually Help

The available fixes are modest but genuine. Both AAA and Recurrent point to the same trick: cool the car down before unplugging it, so a wall outlet — not the battery — absorbs that first burst of energy. Keeping the car in shade, or just using a sunshade, means the compressor doesn’t have to work as hard once a drive starts, and setting the system to recirculate instead of pulling in hot outside air cools the cabin down faster too. No single habit here erases the seasonal hit completely, but combined, they meaningfully shrink it.

The Bottom Line

Summer clearly does cost EV drivers real range — just not nearly as much as winter does. The bigger story might be why the two get such unequal attention: cold-weather testing has existed in a standardized, widely cited form for years, while comparable triple-digit heat testing barely exists yet at all.

Originally published on Latin Times