Strong northerly winds pounded the Waimarino on Sunday, bringing trees down on power lines and causing electricity outages.
Power was lost to a total of 1200 Powerco customers, Powerco network operations manager Phil Marsh said.
Most of those were in Taranaki, and crews were out making repairs on Sunday.
By Monday morning there were still 300 customers in Waiouru and 160 in Raetihi who lacked power.
The outages were caused by a "decent front" passing over, MetService meteorologist Tui McInnes said. It brought north/northwest wind speeds of 65 to 70km/h to Whanganui, and 70-90km/h to Taihape, Waiouru and Raetihi.
The front also brought rain, with heavier falls of 4-5mm an hour in places. The rain was more intense inland, with 32mm falling in 24 hours in Tongariro National Park.
Rain was predicted to continue across the North Island both yesterday and today, McInnes said.
Then a ridge of high pressure from the Tasman Sea should move over New Zealand and bring some improvement tomorrow.
By Thursday the weather should be more settled, but winds will go to the south and it will be colder.
Whanganui could have sub-zero temperatures on Friday morning, and in Waiouru it might hit -4 degrees.