Most merchants who ship temperature-sensitive products use cold packs. Fewer of them have a clear answer to: at what ambient temperature do your cold packs stop protecting the product? That number — your pack tolerance — is the key input WeatherFreight needs to make smarter hold decisions.
What Cold Packs Actually Do
Cold packs work by absorbing heat from the surrounding air and your product. They don't create cold — they delay heat. A 32°F gel pack surrounded by 95°F air will eventually equilibrate with that air. The question is how long it takes, and whether your product survives the transition.
A cold pack is a buffer, not a ceiling. It buys you time — not unlimited protection. Configuring your pack tolerance tells WeatherFreight exactly how much time you're buying.
Configuring Pack Tolerances in WeatherFreight
In the WeatherFreight dashboard, you set a pack tolerance for your products. This tells the AI: 'My cold packs extend the safe window by X°F.' For example, if your chocolate threshold is 85°F and you ship with two gel packs, you might configure a 10°F tolerance — meaning WeatherFreight will approve shipments when forecast temps are up to 95°F, knowing your packs handle the difference.
- No cold packs: set tolerance to 0°F — WeatherFreight holds at your base threshold
- One standard gel pack: typically adds 5–8°F of safe buffer on 2-day routes
- Two gel packs + insulated mailer: typically adds 10–15°F of safe buffer on 2-day routes
- Foam cooler + multiple gel packs: can add 15–20°F on 1–2 day routes
When Thresholds Are Exceeded Even With Packs
When the route forecast exceeds your pack-adjusted threshold, WeatherFreight holds the order automatically. The order note tells you exactly which waypoint triggered the hold and what temperature was forecast — so you're never guessing. The order stays held until the nightly recheck confirms conditions have cleared.
The result: your cold packs are working exactly as hard as they should, and WeatherFreight catches the cases where even your best packaging isn't enough.