text: This Dunea public tap (and several others I've seen) have seasonal=yes, but they have specific operating dates: they are in service from april 1 to november 1 (inclusive).
  
  Source: https://www.dunea.nl/algemeen/home/openbare-tapkranen
  
  (I'm not all that familiar with OSM conventions, but it seems like the 'opening_hours' tag might be more suitable for indicating this than 'seasonal'?)