Parcel networks are built for average volume, so predictable surges push transit times out even when nothing has gone wrong. Treat published transit estimates as optimistic during peak weeks.
The predictable pressure points
- Late November through December, driven by holiday retail volume.
- Early January, when returns flow back through the same network.
- Major sale events, which compress a month of volume into a few days.
- Severe winter weather, which closes highways and grounds aircraft regionally.
- Labour disruptions, which can redirect volume onto other carriers and slow them too.
What to do about it
- Publish your own cut-off dates earlier than the carrier's and communicate them clearly.
- Add buffer days to promised delivery windows rather than promising the carrier's best case.
- Ship earlier in the week; parcels entering the network on a Friday often wait out the weekend.
- Have a second carrier already set up. Switching during a disruption is far harder than switching before one.
- Check the disruption page before quoting a delivery date to a customer.