The average year-round temperature measured from all the weather stations in the Philippines, except Baguio, is . Cooler days are usually felt in the month of January with temperature averaging at and the warmest days, in the month of May with a mean of . Elevation factors significantly in the variation of temperature in the Philippines. In Baguio, with an elevation of above sea level, the mean average is or cooler by about . In 1915, a one-year study was conducted by William H. Brown of the Philippine Journal of Science on top of Mount Banahaw at elevation. The mean temperature measured was , a difference of from the lowland mean temperature.