Captain Connor Hoskin scored a hat trick from a penalty corner and two field goals.
Wanganui will now play Canterbury on Tuesday and have their final pool game against West Coast, with the goal to make the Top 8 for the main quarterfinals.
Further back up the east coast of the island in Timaru, weather conditions were much better at the Under 15 girls national championship tournament, where the Wanganui girls defeated Manawatu B 4-0.
Wanganui scored two goals in each half, with captain Rebecca Baker getting a hat trick, while Georgia Matson got the fourth goal.
Coach Jan Dixon said it took a little while for the team to get sorted, but once they did everything clicked.
Unlike gale winds, her concern was trying to free the stuck boot in the team van so they could retrieve the team's shoes.
The Under 15 girls tournament has 23 teams, with Wanganui in a pool of six.
Their games on Tuesday are against Canterbury and Thames Valley.