Forecast for Otaki Beach, New Zealand (Deterministic)
Issued: 2026-04-05 08:37 NZST
Rest of Today, Sunday 5 April: Cloud cover will thin from overcast skies early on to mainly clear conditions by evening. Light rain will develop around midday and continue through mid-afternoon, bringing a total of 0.5 mm for the day. Winds will be light westerlies shifting to southeasterlies, moving at 1 to 10 km/h with gusts reaching 20 km/h. The low will be 15°C, and the high is expected near 20°C.
Tomorrow, Monday 6 April: Thick cloud cover will persist all day, keeping skies completely overcast. Conditions will remain dry. Easterly winds will strengthen through the day, blowing at 1 to 30 km/h with gusts up to 50 km/h. Temperatures will dip to a low of 12°C overnight, while the daytime high is expected to reach 21°C.
Tuesday 7 April: Overcast skies will dominate the day, with rain holding off until late evening when light to moderate showers arrive, adding 0.5 mm to the daily total. Strong easterly winds will blow at 20 to 30 km/h with gusts up to 60 km/h. The low will settle at 16°C, and the high is expected to reach 20°C.
Wednesday 8 April: Rain will be present from early morning through the evening, with moderate falls expected in the afternoon before clearing overnight. The day will bring a total of 15 mm of rainfall. Winds will shift from easterlies to northwesterlies, moving at 10 to 40 km/h with gusts reaching 70 km/h. Temperatures will fall to a low of 17°C, while the high is expected to sit near 20°C.
Thursday 9 April: Light rain will linger from early morning through late afternoon, gradually clearing by evening and leaving 5 mm of rain for the day. Skies will transition from partly cloudy to clear as the rain moves out. Winds will be northwesterlies turning to northeasterlies, blowing at 5 to 20 km/h with gusts up to 40 km/h. The low will be 15°C, and the high is expected near 19°C.
Existing Vulnerabilities
- The Ōtaki Beach settlement is susceptible to coastal flooding through pathways up the Waitohu and Rangiuru Streams, particularly during large storm events.
- Low-lying areas around the lower Waitohu and Rangiuru Streams, including streets such as Moana Street, Mahoe Street, Marine Parade, and Atkinson Avenue, are identified as the most susceptible to inundation.
- While the settlement is generally protected by sand dunes and the Rangiuru floodgates, there is a residual risk of flooding if the floodgates fail to close or if wave run-up overtops the dunes at low points in the accessways.
- The main evacuation route for the Ōtaki Beach settlement is vulnerable to flooding under higher sea-level rise scenarios, which can be exacerbated by extreme storm-tide events.
Weather Impact Thresholds
- Coastal flooding and inundation: The area is susceptible to flooding from storm tides and wave run-up. A "1% annual exceedance probability" (1-in-100-year) storm event is used as a benchmark for significant coastal inundation risk.
- Heavy Swell: MetService issues a Heavy Swell Warning for the Kapiti-Porirua coast (including Ōtaki) when combined waves of significant height are expected to reach 4 metres or greater from the westerly quarter (NW-SW).
- Severe Thunderstorms: MetService criteria for severe thunderstorms include heavy rain of 25mm/h or more, large hail of 20mm diameter or more, or strong wind gusts of 110km/h or more.
- General Heavy Rain: Widespread rainfall exceeding 50mm within 6 hours or 100mm within 24 hours is generally used as a threshold for severe weather warnings in New Zealand, which can lead to rapid rises in local streams and surface flooding.
Exposed Populations and Assets
- Coastal communities: Residents and properties located along the immediate coastline, particularly in low-lying areas near the Waitohu and Rangiuru Streams, are at the highest risk of inundation.
- Critical infrastructure: The Rangiuru floodgates and the main evacuation route for the Ōtaki Beach settlement are critical assets that, if compromised by flooding, would significantly impact community safety and access.
- Vulnerable groups: As identified in the Ōtaki Floodplain Management Plan, the elderly, disabled, those on low incomes, those in rental housing, and ethnic minorities are considered more vulnerable to the impacts of flooding.
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