Monthly sea level peak for October 2021

The lunar month’s highest tide occurred on 7th October for Waitemata harbour and Great Barrier Island.


The Waitemata harbour tidal gauge measured a mean level of 1.63 metres between 8:45pm and 9:00pm on 7th October which is 12cmm below the October average (2015-2020). The barometric air pressure at the time of the reading was 1006.7 hPa, so when using the inverted barometric adjustment calculation method of 1cm for every 1 hPa, the projected height would have been 1.56 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 1.17 metres between 8:00pm and 8:15pm on 7th October which is 6cm below the October average (2015-2020). The air pressure at the time of the reading was 1002.8 hPa, so when using the inverted barometric adjustment calculation method of 1cm for every 1 hPa, the projected height would have been 1.07 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 Great Barrier Island sea level peak is upward. The tidal gauge data used for this analysis can be found here.



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