high tide

high tide
ˌhigh ˈtide noun
1. [uncountable and countable] the point or time at which the sea reaches its highest level
   OPP  low tide:
    High tide is at seven in the morning.
    at high tide
    The waves became much more powerful at high tide.
2. [singular] the time when something is at its best or most successful:
    the high tide in the party’s fortunes