January is the coolest month in Cebu and from there, the temperatures increase until May - the hottest month. Night time temperatures follow the same pattern. See the table below for more average temperatures.
Rainfall in Cebu can occur during any time of the year, but is most likely during the wet season from May until October. During this time the city is also under the threat of typhoons, although the likelihood of getting hit by one is smaller then if you would stay in Luzon.
Fore more information about the climate of the Philippines, have a look at the climate section.