Filipinos should gird for higher temperatures in May as this month is ''historically'' hot, officials said in an El Nino forum on Monday.

''Not yet,'' said Science and Technology Secretary Renato Solidum replied to a reporter's question if cooler weather may be expected in May.

Later in the day, the country's highest heat index soared to 51 degrees Celsius in Dagupan City, Pangasinan. The heat index for Metro Manila went down slightly to 41 degrees Celsius at the Ninoy Aquino International Airport in Pasay,

Marcelino Villafuerte, deputy administrator for research and development of the Philippine Atmospheric, Geophysical and Astronomical Services (Pagasa) said:'' According to our analysis historically, May is hotter so are still expecting to have warmer temperature.''

Villafuerte said that for Metro Manila, temperatures can range from 36.5 degrees Celsius to 38. 3 degrees Celsius, with the latter as maximum forecast temperature.

Metro Manila temperatures reached a new high on Friday of 38.8 degrees Celsius at the Ninoy Aquino International Airport (NAIA). DMS