Wellington

Wellington sits on the southern tip of the North Island of New Zealand, on a deep harbour that opens south through the entrance at Pencarrow Head into Cook Strait — the 22-kilometre channel separating the North and South Islands and one of the most challenging stretches of water in the South Pacific. The tide here is a moderate semidiurnal signal — two highs and two lows of comparable size each day, twelve and a half hours apart — with a mean range at Wellington Harbour of about 1.0 metre, climbing past 1.4 metres on spring tides and dropping near 0.6 on neaps. The pattern is small in absolute terms because the city sits at the amphidromic node of the New Zealand tidal regime, where the propagating tide cancels out by phase opposition. What matters more on a day-to-day basis is Cook Strait current, which runs hard between the two islands at the change of tide — the Interislander and Bluebridge ferries between Wellington and Picton on the South Island time their passages around the slack, and the strait can produce four-metre confused seas when the tide opposes a southerly gale. The Wellington fault runs directly under the harbour and the city's seawalls were rebuilt after the 2016 Kaikōura earthquake, which uplifted the South Island coast across the strait by up to six metres in places. Oriental Bay's beach, the rocky intertidal at Lyall Bay and Houghton Bay south of the airport, the working container port at Aotea Quay, and the bach-strewn coastlines of Eastbourne and Days Bay across the harbour all read the table for different windows. Land Information New Zealand (LINZ) publishes the authoritative tide tables; Open-Meteo Marine drives the gridded predictions on this site.