Storm-tide red alerts are the highest high tide (also known as king tides) dates that Emergency Managers and Coastal Hazard Managers should write in their diaries and keep an eye on adverse weather (low barometric pressure, onshore winds), river levels and sea conditions (waves and swell).
The dates below are averaged across New Zealand. See tide forecasts for specific locations.
The following table shows the 2023 dates of the highest high-tide "red alert" dates, and the lowest high-tide dates (formerly known as "carefree"). It also includes dates when the moon's orbit brings it closest to [perigee] and furthest from [apogee] the earth.
2023: Range of dates collated across New Zealand
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Red-alert dates (highest high tides) |
Lowest high tides (formerly ‘carefree’) |
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[actual lunar perigee date] |
[actual lunar apogee date] |
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21-27 January [22 Jan] |
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19-24 February [19 February] |
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2-3 March [3 March] |
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20-24 March [20 March] |
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30 March-1 April [31 March] |
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27-29 April [28 April] |
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27-28 May [26 May] |
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7-8 June [7 June] |
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4-8 July [5 July] |
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1-6 August [2 August] |
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30 August- 4 September [31 September] |
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10 September [12 September] |
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28 September-3 October [38 September] |
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9 October [9 October] |
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28-31 October [26 October] |
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6-8 November [7 November] |
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5-7 December [5 December] |
Visual representation of this calendar:
2023 calendar of red alert high tide dates.
There is a printable version of the 2023 calendar available for download [PDF 185KB].
Regional red alert days
Red alert tide days are available for different regions throughout New Zealand.
- West Auckland
- East Auckland
- Firth of Thames
- Bay of Plenty
- Taranaki
- Nelson-Tasman
- West Coast (South Island)
- Christchurch
- Dunedin
- Wellington
Further information
High perigean-spring tides, colloquially known as "king tides", peak 1–2 days after New or Full Moon when Moon is in its perigee (i.e., when it is closest to the Earth during its 27½ day elliptical circuit around the Earth), but dates of highest tides vary around New Zealand.
In 2023 the Moon's closest perigee occurs on 31 August and coincides with a Full Moon, with next closest on 7 June (Full Moon).
For the year 2023, "red-alert" dates cluster around very high tides (perigean-spring tides) that peak 1–2 days after New or Full Moon when Moon is in its perigee and lowest high-tide (formerly “carefree”) dates cluster around lower high tides after First or Third Quarter when Moon is close to its apogee.
Times for perigee, apogee and New and Full Moon in UTC (add 12 hours for NZST).
