MetService has issued a Heavy Swell Warning for the Kapiti–Porirua Coast, spanning the stretch between Ōtaki and Cape Terawhiti. The warning is in effect from 2am to 9am on Thursday 18 September, covering a seven-hour period.
Northwest swells are forecast to build to 3–3.5 metres, with combined wave heights peaking at 4–4.5 metres. A swell period of around 10 seconds will give the sea considerable energy, while wind waves of approximately 3 metres will add to an already difficult sea state.
The most hazardous window will coincide with the morning high tides. Makara Beach is due to reach high tide at 6:23am Thursday, with the Ōtaki River Entrance following at 7:16am. Conditions are expected to ease once mid-morning has passed.
An Orange Strong Wind Warning is also in place for Wairarapa and the Tararua District, running for four hours from 8am to midday on Thursday. Severe gale northwesterlies are forecast, with gusts in exposed locations potentially hitting 120 km/h. MetService regards the likelihood of escalation to a Red Warning as low, though the potential for significant disruption remains. Trees, powerlines, and unsecured structures are all at risk, and drivers, particularly those in high-sided vehicles or on motorcycles, should anticipate hazardous conditions on exposed roads.
SH1 AKL HBR BRIDGE - WIND WARNING Strong wind gusts are expected to affect the Harbour Bridge today between 9am and 2pm. Speed restrictions and lane reductions are likely, while temporary full closures may be required. Caution is advised. ^KF pic.twitter.com/2otSAh5XEl — NZ Transport Agency - Auckland & Northland (@nztaaklnth) September 17, 2025
With heavy seas and powerful winds forecast for Thursday morning, coastal users across the lower North Island face a challenging few hours. Authorities are recommending people secure any property that could be shifted or lifted by strong gusts, avoid launching boats during the peak swell period, take extra care on roads and watch for debris, and keep up to date with the latest forecasts through MetService.
