MANILA, Philippines -- The maximum temperatures in Metro Manila reached its highs again Wednesday with little relief from the heat in sight after the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) said rains would come in the second half of June yet.

According to PAGASA?s weather forecasting section, the maximum temperature in Metro Manila reached 37.3 degrees Celsius, the highest for 2010 so far, and the same reading for April 28 and May 17. Friday?s reading was taken at 3 p.m. at the agency?s Science Garden facility in Diliman, Quezon City.

?We expect fair but hot weather in the next three to four days except for isolated rainshowers and thunderstorms in the afternoons and evenings,? said Cris Perez of the PAGASA weather forecasting section.

Edna Janillo, assistant weather service chief of PAGASA?s Climatology and Agrometeorological Division, said that because of the ongoing El Niño phenomenon, ?our onset of the rainy season will be slightly delayed to the second week of June.?

She explained that normally, the rainy season comes into the country in the second half of May to the first half of June.

?Although El Niño is weakening, we will still feel the lingering effects. There is a lag in the time we would feel the effects of El Nino,? Juanillo said.

El Nino is the abnormal warming of sea surface temperature in the Pacific Ocean that causes droughts in some parts of the world.

?Weather systems can form very quickly. But as of the present, we still have southeasterly winds. We have yet to detect signs of the southwest wind (known locally as ?Habagat),? she said.

Besides the coming of the southwest monsoon, Juanillo explained that there were many factors to consider before PAGASA can declare the end of the summer or dry months and the start of the rainy season. ?There is weakening of the ridge of the high pressure area in China, consistent rainfall and wind direction,? she said.

Juanillo also advised to watch out for weather systems entering the country. The intertropical convergence zone (ITCZ) affecting Mindanao and Visayas is normal this time of year, according to her.

The ITCZ is the region near the equator where trade winds meet, forming low pressure areas that bring wind and rain.

According to the agency?s weather forecast, Visayas, Mindanao and Palawan will experience mostly cloudy skies with scattered rainshowers and thunderstorms due to the ITCZ. The rest of the country including Metro Manila will have partly cloudy to cloudy skies with isolated rainshowers or thunderstorms mostly in the afternoon or evening.