Definition(s)
MHHW
For regions with semi-diurnal or mixed semi-diurnal tides, the mean of the higher of the two high tides that occur each tidal day, determined over the period of water level observations.
Source: API RP 2MET, Derivation of Metocean Design and Operating Conditions, First Edition, November 2014. Global Standards
MHHW
Mean higher high water.
Source: API RP 2MET, Derivation of Metocean Design and Operating Conditions, First Edition, November 2014. Global Standards