I looking for reliable meteorological information about Indonesia. More specifically: monthly precipitations and mean temperatures, at the regional level or lower.
However, I think using gridded data is an ideal choice especially for monthly temperature and precipitation. So, for monthly temperature, I recommend gridded data produced by university of Delaware (v4.01, 1901-2014):
You can use a high resolution gridded data of CHIRPS 0.05 degree by 0.05 degree. They have one specially for Indonesia. It is freely available and easily downloaded from their website.
Download data meteorology and climate in In Indonesia, please visit the site http://dataonline.bmkg.go.id/home. First you should be Register. Good Luck