Many Dutch ice rinks opened last week despite temperatures of around 20 degrees Celsius. The early opening has prompted questions about whether the skating season should start later, since higher outdoor temperatures require more energy to create and maintain an ice surface. The Netherlands has 22 permanent ice rinks, which decide independently when to open; most open in early October. Some rink managers say delaying the season is not feasible because of the competition calendars of the Dutch skating association KNSB and the international skating association ISU. They say the skating season will not change unless the ISU calendar changes.