<p>We just had a very low low tide in the UK, an equinoctial tide on the 12th of March that was calculated as -0.13m above chart datum, i.e 13cm below the 'Lowest Astronomical Tide'.</p>
<p>Check here for tidal heights- <a href="https://ntslf.org/tides/hilo" rel="nofollow noreferrer">https://ntslf.org/tides/hilo</a></p>
<p>How can a tide be lower than the 'Lowest Astronomical Tide' on a chart?</p>

CC BY-SA 4.0
2024-03-15T06:23:49.983Z
air pressure and wind will do that.
trond hansen
CC BY-SA 4.0
2024-03-15T07:41:23.963Z
Interesting…some of these tide heights appear to be predicted years/decades in advance…can air pressure and wind on a particular day be accurately predicted that far in advance?
Captainpadlock
<sea-level><mapping><tides>
How can a tidal height be lower than 'Chart Datum'/'LAT' e.g 'Lowest Astronomical Tide'?
Captainpadlock
# How can a tidal height be lower than 'Chart Datum'/'LAT' e.g 'Lowest Astronomical Tide'?

(Asked by: username_0 on 2024-03-14)

We just had a very low low tide in the UK, an equinoctial tide on the 12th of March that was calculated as -0.13m above chart datum, i.e 13cm below the 'Lowest Astronomical Tide'.

Check here for tidal heights- <https://ntslf.org/tides/hilo>

How can a tide be lower than the 'Lowest Astronomical Tide' on a chart?

**Tags:** sea-level, mapping, tides

> **Comments:**
> **username_1**: air pressure and wind will do that.  
> **username_0**: Interesting…some of these tide heights appear to be predicted years/decades in advance…can air pressure and wind on a particular day be accurately predicted that far in advance?  

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## 0 answers

