Guide · June 22, 2026
A shipping container with its own climate. It's how a box of frozen seafood crosses an ocean and a port without ever thawing — and why the drayage clock is even tighter than usual.
A reefer container — short for "refrigerated" — is an intermodal shipping container with a built-in refrigeration unit that controls the temperature inside. Unlike a standard dry container, which is just an insulated steel box, a reefer actively heats or cools its cargo to a set point and holds it there across ship, rail and truck. It plugs into power on the vessel and at the terminal, and runs off a generator ("genset") while it's on a chassis being trucked.
Reefers come in the same external footprints as dry boxes — most commonly 20 ft and 40 ft high cube — though the refrigeration machinery means slightly less interior space. Typical set points range from deep-frozen (around −20°F / −29°C and below) for seafood and ice cream up to chilled (around 55°F / 13°C) for produce, with precise control in between for pharma, flowers and other sensitive cargo.
Pulling a reefer off the terminal isn't the same job as a dry box. The cargo is temperature-critical, so the move is more time-sensitive, the container has to stay powered (genset on the chassis, or a quick plug-in), and any delay — a missed appointment, a demurrage hold — risks the load itself, not just a storage fee. That makes managing the Last Free Day and the appointment even more important on a reefer than on a standard container drayage move. If you're running cold-chain freight through the Ports of Seattle or Tacoma, the carrier's reliability is the cargo's insurance.
A refrigerated intermodal shipping container with a built-in unit that actively controls temperature, keeping cargo frozen, chilled or climate-controlled across ship, rail and truck.
Most commonly 20 ft and 40 ft high cube, matching standard dry-container footprints, though the refrigeration unit slightly reduces usable interior space.
Typically anywhere from around −20°F (−29°C) or colder for frozen goods up to about 55°F (13°C) for produce, with precise set-point control for sensitive cargo like pharmaceuticals.
The cargo is temperature-critical, so the container must stay powered (via a genset on the chassis) and the move is more time-sensitive — a delay risks the load itself, making appointment and Last Free Day management even more critical.