Monthly sea level peak for February 2021

The lunar month’s highest tide occurred between 15th and 16th February 2021 for Waitemata harbour and Great Barrier Island.

The Waitemata harbour tidal gauge measured a mean level of 1.52 metres between 10:45am and 11:00am on 15th February which is 19cm below the February average 2015-2020). The barometric air pressure at the time of the reading was 1008.3 hPa, so when using the inverted barometric adjustment calculation method of 1cm for every 1 hPa, the projected height would have been 1.47 metres at the mean sea level pressure of 1013 hPa. More on meteorological effects on tides can be found here.

The ongoing trend between 2014 to 2021 for the Waitemata harbour sea level peak is downward. The tidal gauge data used for this analysis can be found here.




The Great Barrier Island tidal gauge measured a mean level of 1.03 metres between 11:00am and 11:15am on 16th February. The air pressure at the time of the reading was 1002.4 hPa, so when using the inverted barometric adjustment calculation method of 1cm for every 1 hPa, the projected height would have been 0.92 metres at the mean sea level pressure of 1013 hPa. More on meteorological effects on tides can be found here.


Note# A non tidal 60cm tsunami event occurred on 11 February from an M 7.7 earthquake near New Caledonia reaching to 1.23 metres mean sea level. This is not included in the data and graph due to the non tidal nature of the peak.

The ongoing trend between 2014 to 2021 for Great Barrier Island sea level peak is a flat trend. The tidal gauge data used for this analysis can be found here.






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