Monthly sea level peaks for September 2020

Updated: Oct 26, 2020

The lunar month’s highest tide occurred between 16th and 23rd September 2020 for Waitemata harbour and Great Barrier Island.

The Waitemata harbour tidal gauge measured a mean level of 1.71 metres between 9:45pm and 10:00pm on 20th September which 4cm below the 2015 to 2019 September period. The barometric air pressure at the time of the reading was 1029.0 hPa, so when using the inverted barometric adjustment calculation method of 1cm for every 1 hPa, the projected height would have been 1.87 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 2020 for the Waitemata harbour sea level peak is currently flat. 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 7:45pm and 8.00pm on 20th August. The air pressure at the time of the reading was 1025.1hPa, so when using the inverted barometric adjustment calculation method of 1cm for every 1 hPa, the projected height would have been 1.29 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 2020 for Great Barrier Island sea level peak is a slight upward trend. The tidal gauge data used for this analysis can be found here.




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