Summer Heat vs. Speed: What Really Impacts EV Range?
Data from Geotab shows that driving speed has a greater impact on EV range than summer heat, especially for larger vehicles on longer trips
OAKVILLE, ON, July 2, 2025 /PRNewswire/ - As summer heatwaves roll in, many electric vehicle (EV) drivers worry about how high temperatures, and heavy air conditioning use, will affect their range. But data from Geotab Inc. and its affiliates ("Geotab"), a global leader in connected vehicle solutions and asset management, shows that while hot weather does have an effect, driving speed can be the single biggest factor in range loss.
Using anonymized telematics data from over 3 million trips,* Geotab has compared how temperature and speed affect energy use in light-duty EVs, including sedans and cargo vans. At higher speeds (50-80mph) in hot temperatures (86°F/30°C), aerodynamic drag has a far greater effect on range than cabin cooling.
The data shows that even modest increases in speed lead to steep range losses. For example, a 65 kWh electric van cruising at 50 mph in 86 °F heat with the air conditioning on has a typical range of around 143 miles. Increase that speed to 60 mph, and range drops to 121 miles. At 70 mph it falls further to 103 miles, and by 80 mph, you're down to just 88 miles. That's a 39% drop in range between 50 and 80 mph.
The pattern is similar for electric sedans, though they're slightly more aerodynamic. At 50 mph at 86°F, you can expect 277 miles. At 60 mph: 251 miles. At 70 mph: 226 miles. And at 80 mph: 200 miles - a 28% drop from the most efficient cruising speed.
This sharp decline comes down to physics. The faster you go, the more your car has to fight air resistance. Aerodynamic drag increases with the square of your speed, so doubling your speed requires four times the energy just to overcome wind resistance. That's far more than your A/C system will ever use.
"Drivers tend to worry about using the aircon in hot weather, but our data shows that your right foot can make the biggest difference, particularly at high speeds," said Charlotte Argue, Senior Manager, Sustainability, at Geotab. "Just slowing down by 10 or 15 mph can extend your range by 20–30%, depending on the vehicle."
Temperature still matters; but mostly at low speeds
In summer, the impact of heat is largely visible at lower speeds, where drag is otherwise minimal. In these conditions, the constant draw from air conditioning becomes more noticeable. But the faster you drive, the less significant temperature becomes relative to the energy required to maintain speed.
"Modern EVs have increasingly large batteries, and many can comfortably handle most daily driving - including fleet routes - on a single charge," added Argue. "But range, on EVs or ICE vehicles, will always vary with real-world conditions: temperature, topography, traffic, and yes, speed."
Practical steps to maximise EV range this summer
Geotab recommends a few simple techniques to help drivers stretch range without compromising comfort:
- Reduce your speed - even small reductions in highway speed can make a big difference. For many vehicles, dropping from 70 mph to 60 mph can add 10–20% more range.
- Precondition the cabin while the vehicle is still plugged in, using gridpower rather than the battery.
- Use A/C efficiently – start cool, use recirculate mode, and if equipped, prioritise seat ventilation over full cabin cooling.
- Avoid aggressive acceleration and braking, and make the most of regenerative braking.
- Park in the shade to keep the cabin cool and reduce A/C load at start-up.
- Avoid fast charging during extreme heat, which can put additional strain on the battery and may contribute to faster long-term degradation.
Notes to editors
About the study
*This Geotab analysis is based on aggregated and anonymized telematics data.The sedan was modeled by analyzing 350,000 trips from 500 sedans, totaling over 180,000 hours of driving. The light cargo van was modeled by analyzing 2.8 million trips from 2000 vans, totaling over 370,000 hours of driving. Both models were adjusted to represent a 65 kWh battery.
About Geotab
Geotab is a global leader in connected vehicle and asset solutions, empowering fleet efficiency and management. We leverage advanced data analytics and AI to transform fleet performance, safety, and sustainability, reducing cost and driving efficiency. Backed by top data scientists and engineers, we serve over 55,000 global customers, processing 80 billion data points daily from more than 4.7 million vehicle subscriptions. Geotab is trusted by Fortune 500 organizations, mid-sized fleets, and the largest public sector fleets in the world, including the US Federal Government. Committed to data security and privacy, we hold FIPS 140-3 and FedRAMP authorizations. Our open platform, ecosystem of outstanding partners, and Marketplace deliver hundreds of fleet-ready third-party solutions. This year, we're celebrating 25 years of innovation. Learn more at www.geotab.com and follow us on LinkedIn or visit Geotab News and Views.
SOURCE Geotab Inc.
Share this article