Freight moves year-round, but summer adds a layer of risk that most shippers only think about after something goes wrong. A load of produce leaving California in early June can sit in a trailer at 95°F during a lunch break stop in Arizona. A pallet of insulin traveling cross-country through the South can swing outside its required 2°C to 8°C range in the time it takes a driver to fuel up and grab coffee. These aren’t edge cases. They’re standard summer scenarios for anyone moving temperature-sensitive freight in the U.S.
The FDA estimates the pharmaceutical industry loses $35 billion a year to cold chain failures, and a meaningful share of that happens between June and September, when ambient temperatures across most of the country climb past safe thresholds for sensitive products. For food and beverage shippers, the pressure is just as real. Produce season is already in full swing, reefer capacity is tightening, and the margin between a clean delivery and a spoiled load narrows fast.
If you’re shipping pharmaceuticals, biologics, fresh produce, dairy, or any other perishable commodity this summer, the decisions you make right now on carrier selection, routing, and packaging will determine how the next three months go.
Why Summer Creates Different Problems Than Winter
Most shippers treat winter as the dangerous season for freight, and for good reason. Ice, road closures, and transit delays create real headaches in December and January. But summer creates a different problem: sustained ambient heat that works against temperature-controlled cargo at every transfer point.
A refrigerated truck maintains its interior temperature while moving. But every time a driver opens the trailer doors at a dock, or a load sits at a distribution center without being plugged into a shore power unit, the interior temperature climbs. For a dry goods pallet, that’s a minor inconvenience. For a shipment of biologics or fresh seafood, it can mean the entire load is compromised.
The challenge compounds when you’re using LTL shipping for smaller temperature-controlled loads. In LTL, your freight shares trailer space with other shipments and makes multiple stops along the route. Each stop is another opportunity for temperature exposure, and in summer, those exposures stack up faster than they do in cooler months.
States like California, Florida, and Texas see some of the heaviest outbound perishable freight volumes during summer, and they’re also the states where ambient temperatures make cold chain management the most demanding. Reefer capacity in those lanes tightens as produce season accelerates, which means shippers who wait until the last minute to book are often choosing between poor carrier options and delayed pickups.
What Pharma Shippers Need to Account For
Most medicines that require refrigeration must be kept between 36°F and 46°F, and a deviation of even a few degrees can spoil the product entirely. For biologics, the tolerance window is often tighter, sometimes within 1°C to 2°C, and these products have become a much larger share of what’s moving through pharmaceutical supply chains. More than 85% of biologics require temperature-controlled manufacturing, storage, and distribution across their entire lifecycle.
The regulatory side adds another layer. Products that fall under FDA oversight, including vaccines, insulin, and specialty medications, require documentation of temperature conditions throughout transit. That means your carrier needs to be equipped for monitoring, and your cold chain logistics process needs to account for it before the shipment leaves the dock, not after something goes wrong.
The practical reality for pharma shippers is that summer requires more lead time on carrier selection, tighter scrutiny of routing, and packaging that’s been validated to hold temperature through multiple transfer points, not just ideal conditions.
Perishable Food Freight Faces the Same Constraints
Food shippers run into identical pressure, just with different products and regulatory frameworks. The Food Safety Modernization Act sets sanitary transport requirements for many food commodities, and carriers hauling fresh produce, dairy, or meat need to meet those standards consistently. In summer, the operational margin for error shrinks because ambient conditions are working against the reefer system from the moment freight is loaded.
Fresh produce is particularly time-sensitive. A load of berries or leafy greens has a tight window between harvest and delivery, and a single transit delay in summer heat can push product past its safe handling date. The cost isn’t just the spoiled load. It’s the customer relationship and the likelihood that the next order goes to a competitor who delivered clean.
For food shippers using LTL freight services, one practical step is being explicit about temperature requirements when booking, not just selecting “refrigerated” as a service type. Carriers need to know the minimum and maximum thresholds for your product so they can plan accordingly. A load with a 35°F requirement and a load with a 28°F requirement use the same reefer equipment very differently.
The Carrier Question
Temperature-controlled freight in summer is a capacity story as much as a logistics one. Reefer trucks represent a smaller share of the total carrier fleet than dry vans, and demand for that capacity spikes from late May through August. Shippers who haven’t planned ahead often find themselves with fewer options and higher rates at the exact moment they need a reliable carrier most.
Working with a platform that connects you to multiple vetted carriers is more useful here than negotiating with one carrier at a time. GoShip lets you compare reefer LTL and FTL rates across a carrier network instantly, which matters when capacity is tight and you need a dependable option quickly.
Beyond booking lead time, it’s worth asking about your carrier’s pre-cooling practices. A reefer trailer that hasn’t been brought down to the target temperature before loading will spend the first stretch of transit pulling cargo temperature down from ambient, which is the wrong direction for sensitive freight. Good carriers build pre-cooling into their standard process. It’s a reasonable thing to confirm before handing over a temperature-sensitive load.
Packaging Does the Work Between Handoffs
Even a well-managed reefer carrier can’t fully protect a shipment that’s packaged inadequately for summer conditions. Insulated liners, gel packs calibrated to your product’s temperature range, and thermal blankets all extend the hold time during transfer points when refrigeration isn’t running. For pharmaceutical shipments, packaging needs to be validated for the ambient temperatures in the specific lanes you’re using, not just average conditions.
For food shippers, the calculus is similar. A load of frozen meat that leaves a Chicago warehouse in good condition but passes through a Kansas yard at 108°F without adequate insulation is a problem that packaging choices made in March didn’t anticipate. Summer shipping in hot weather requires packaging specs that reflect real peak conditions, not annual averages.
Transit Routing Is Underrated
One variable that gets less attention than carrier selection or packaging is routing, specifically which lanes and transfer points your freight moves through. A shipment from New Jersey to Dallas can take different paths depending on the carrier’s network, and some of those paths go through areas that are significantly hotter than others. For high-value pharmaceutical loads, it’s worth asking your carrier specifically about how they route temperature-sensitive freight during summer. The carriers who have a clear answer have thought carefully about this. The ones who don’t have a clear answer are worth noting.
For produce and perishable food, transit time is often the most important variable. Fewer days in transit means less cumulative temperature exposure. When you’re comparing carrier options for a perishable load, a slightly higher rate for a faster transit time often pays for itself in spoilage prevention, and it’s a trade-off that’s easier to evaluate when you can see multiple carrier options side by side.
Getting a Quote While Capacity Is Still Available
Reefer capacity is already tight and stays that way through early September, and rates reflect it. Shippers who lock in carriers now have more options than those who wait until a customer order forces the issue mid-July.
You can get a free instant quote for refrigerated LTL and FTL freight at GoShip and compare rates across carriers without committing to anything, which is a useful way to see what capacity actually looks like in your lanes right now.