What should I actually be doing differently for my EV in extreme heat vs. cold?
Been putting off asking this because it felt like a silly question, but with this heat wave the last two weeks I've caught myself just parking wherever's open at the grocery store without thinking about it, sun or shade. Never occurred to me that it might matter for the battery the way it would for milk left in the trunk. And I know I'm going to have the opposite problem come January — first winter with this car, and I honestly don't know what I actually need to be doing differently versus what's just internet noise. Is there anything real here, or am I overthinking two different seasons at once?
Filed under: General EV Talk
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15 answers
15 ANSWERS
@icewardenJuly 22, 2026
Eight years of both extremes here, not overthinking it. Heat: shade or garage when you can get it, doesn't have to be every single time, just don't make a habit of baking it in direct sun all summer if you have a choice — sustained heat is harder on the pack long-term than a few afternoons ever will be. Cold: precondition before you drive if the car lets you schedule it from the app while still plugged in, that warms the cabin off wall power instead of battery power, and budget real range loss once it's actually cold, not just chilly — I plan for 30-40% off the top around -20°C, doesn't come back until it warms up. Neither season damages anything on its own if you're reasonable about it.
Matches my numbers out of Michigan too. Had a stretch a few winters back that sat around -18 for about a week straight and watched my normal charge estimate lose almost 40% before I adjusted my routine. Not broken, just cold.
Nobody's mentioned what happens if you're not driving it at all for a while. I close the farm stand for a few weeks in the off season and the car just sits. Is there an actual number I should charge to before I walk away, or is topping it off to 100% and forgetting about it fine?
Not fine long-term. A pack sitting at a full or near-empty state of charge for weeks degrades faster than one sitting in the middle. Somewhere around 50-60% is the sweet spot if it's parked more than a couple weeks. A few days at 100% before a trip isn't the same thing — that's not what causes the damage.
wait so charging it all the way up is actually bad? i thought more charge was always safer to have just in case
Safer for range anxiety, not safer for the battery. Full charge for an actual drive the next day is fine — the problem is leaving it sitting at full or near-empty for weeks with nowhere to go. Different situation than a normal charge cycle.
The precondition-before-charging point is worth separating from precondition-before-driving, they're solving different problems. Warming the pack before you plug into a fast charger gets you a meaningfully quicker session, because cold cell chemistry won't accept high current no matter how good the charger is. Warming the cabin before you unplug and drive is a different move entirely — that heat comes off the wall while you're still connected instead of off the pack once you're moving. In sustained -25°C conditions, the difference between doing both and skipping one shows up clearly in both charge time and the first ten minutes of driving.
That's helpful, thank you. Does scheduling that cabin warmup from the app run up the electric bill in any meaningful way, or is it small enough not to worry about?
Small next to what heating that same cabin off the battery would cost you in range, which is really the comparison that matters. It's coming off your house circuit for maybe 10-15 minutes before you unplug, not a meaningful line on the bill. The cost was always going to be paid one way or the other — this way it's paid in home electricity instead of range you needed for the drive.
Is parking in shade mostly about protecting range for that one drive, or is it more about long-term degradation from repeated heat soak?
Maine winters get comparable to the -18°C someone mentioned above, watched my own estimate drop close to that 30-40% range in a stretch like that last February. One thing that actually helped besides preconditioning: parking nose-in toward the garage door instead of backing in, so the charge port faces where I'm walking from and the cable and port sit exposed for less time before I plug in. Small thing, but noticeable on the coldest mornings.
@twigcoralJuly 22, 2026
Coming from Florida so the heat side is the one I actually know something about firsthand, but does it take a specific temperature before it's actually a problem, or is any hot day bad for it?
Not any hot day, no. Occasional 95-100°F afternoons parked outside aren't what causes measurable degradation. It's sustained exposure well into the 100s+ for extended stretches — more like a car that lives outside through a genuinely brutal summer for months — that's when the accelerated wear shows up in the data. A week of heat isn't the same risk as a whole season of it.
@static_jellyJuly 22, 2026
Site's actually got a whole page on the cold-charging side of this if anyone wants the longer version instead of piecing it together from a comment thread. Worth a read before the first real cold snap hits, not during it.
reading a manual before an emergency, wild concept
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