The national arrival of Sinterklaas in Vianen is set to attract around 20,000 visitors tomorrow, with mostly dry weather anticipated for the event. Though cloudy and breezy, temperatures will remain cool at approximately 8 to 9 degrees Celsius. While Vianen may see favorable conditions, other regions could experience rain and possible thunderstorms, especially on Sunday. Viewers can catch the live broadcast of the event on NPO3 starting at noon, as organizers remain optimistic about the weather.