Andrew Moseman has covered science, technology, and transportation for publications such as The Atlantic, Inverse, Insider, Outside, and MIT Technology Review. He was previously digital director of Popular Mechanics and now serves as online communications editor at Caltech. He is based in Los Angeles. Read More
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Extreme Heat Is Roasting Packages
Our deliver-everything era is crashing into a hotter planet.

Heatmap Illustration/Getty Images
When my phone dinged with the delivery notification, I raced outside to get the package into my apartment. I was not afraid of parcel theft, but of the sauna-like temps outside. One of 2023’s unbearable summer heat waves had descended upon Los Angeles, and my wife’s package of cosmetics contained creams and solutions with very specific instructions about how they should be safely stored. They weren’t the kinds of things you want to leave out in the sun as the thermometer approaches 100.
This year’s record-setting temperatures come at a time when Americans have fully embraced the power of online shopping. We have just about everything delivered — not just the durable goods that have always been sent through the mail, but perishable items like makeup, medicine, and meal prep kits. That adds up to a lot of extra deliveries happening during the dog days of a climate-changed summer.
The first thing to worry about are the men and women in the trucks. While office workers can turn up the air conditioning to mitigate extreme summer temperatures, delivery drivers spend their sweltering days getting in and out of vehicles that may or may not have AC. This summer, a U.S Postal Service letter carrier in Texas died while working on a day with a heat index in excess of 110 degrees Fahrenheit. Media reports have found drivers from parcel services like UPS and FedEx who say they suffer heat exhaustion from working in a truck with only a small fan to keep them cool, or are afraid to spend too much time in the vehicle’s unventilated cargo hold on a hot day.
Those organizations are now making changes to counter the increasingly dangerous summers. UPS reached a deal with its union to put AC in new trucks bought after January 1, 2024, and to retrofit old ones with solutions such as heat shields. In some areas, USPS has considered changing its delivery schedule, allowing drivers to start earlier in the morning to beat the afternoon heat.
These changes should help to protect drivers. But what about their deliveries? Packages sent during summer spend plenty of time in hot distribution centers and in the blistering backs of trucks where drivers fear to tread. If nobody’s home when the delivery comes, boxes spend hours or days in sweltering outdoors temperatures. The phenomenon has led to many social media conversations in which users ask one another whether their boxes full of delicate fragrances or HelloFresh meal prep kits are still safe to use or eat after long exposure to this insufferable summer.
Meal kits are shipped in temperature-controlled packaging meant to endure a day or two outside, with insulation and cold packs in place to keep food from warming up in transit and spoiling before it ever gets in the fridge. Abigail Dreher, the associate director of corporate communications for HelloFresh, told me that the company already optimizes how temperature-resistant it makes its packaging based on climate. Somebody receiving the ingredients to make golden chicken schnitzel in Tucson, Arizona will have their food packaged with more cold-keeping power than someone who, say, orders a kit for chicken wings in Buffalo.
As summer temperatures around the nation rise, though, shippers will need to use more and more insulating materials. “We test for temperatures up to 115 degrees Fahrenheit,” Dreher says, “and every year we plan for a 3-degree Fahrenheit average increase in temperatures, which increases the amount of cold-packaging going to hot destinations used year over year.” So far, however, HelloFresh has been able to offset this increase in packaging by using less insulation for meal kits bound for colder places.
That’s good news for sustainability, because while many insulating layers used for shipping are curbside-recyclable, some must be thrown away — including those gel packs used to keep shipments cold. “We are continuously searching for biodegradable/compostable alternatives to our gel packs,” Dreher says. “However, we do not yet have a solution that can be sourced at the scale which we need.”
The same trend goes for not only food but any contents that must be temperature-controlled. Medication, says GoodRx, “can change physically or chemically” when moved or stored in extreme temperatures. Medicines like insulin that must stay cool come in cold packaging, and many temperature-sensitive drugs are shipped with color-changing test strips or some other safeguard meant to tell the recipient whether the contents have been exposed to extreme temps.
The most likely outcome is that more shoppers will be caught in no-man's land upon opening their packages. If that meal kit delivery has sat under the sun for hours — and the steak inside is still cool, thanks to the packaging, but maybe not as cold as it once was — should you still cook and eat it? If that box of medicines endured a day in the 100-degree heat, but doesn’t look any different, should you take them, or send them back? A sea of judgment calls await.
Another possibility: higher shipping costs. Merchants who sell heat-sensitive products already have a variety of temperature controlled shipping options at their disposal, from specialized hardy containers to keep cargo at room temperature or colder to real-time temperature monitoring to “cold chain centers” to keep items cool while they await distribution. In addition, sellers may be tempted to choose faster shipping options to minimize the in-transit exposure to summer temperatures — costs that, no doubt, will be passed on to the home shopper.
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