At least 25 people are known to have died but blocked roads and downed communications lines mean the true impact on rural areas is not yet clear.
Extensive crop damage is feared in the agricultural province of Cagayan.
The storm, which packs a 900km (550 mile) rain band and strong winds, is heading towards southern China.
It poses a "severe threat" to Hong Kong, the territory's observatory said, urging residents to stay on high alert.
In the Philippines, it made landfall at Baggao, in the north-east of the main island of Luzon, at about 01:40 local time on Saturday (17:40 GMT on Friday) and left some 20 hours later.
Originally a super typhoon billed as the strongest storm of 2018, it lost some of its strength on landfall.
Five million people were in its path and more than 100,000 sheltered in temporary centres.
Francis Tolentino, a presidential spokesman and disaster response coordinator, said almost all the deaths had been caused by landslides in the Cordillera and Nueva Vizcaya regions.
He added that reports from other areas were still coming in.
One person was killed by a falling tree in the province of Ilocos Sur, Mr Tolentino said.