(UPDATE) THE weakening northeast monsoon or "amihan" is a sign that the dry season could start any day soon, the Philippine Atmospheric, Geophysical and Astronomical Services Administration (Pagasa) said on Friday.

Pagasa weather specialist Robert Badrina said the agency may eventually declare the end of the northeast monsoon, which has been bringing localized thunderstorms and isolated rain showers over Metro Manila and the rest of the country.

In its 5 a.m. advisory, Pagasa said it has not monitored any tropical cyclone or low-pressure area inside or outside the country's area of responsibility.

The easterlies — winds coming from the east that pass through the Pacific Ocean and carry humid and warm weather — are affecting the country, Badrina said.

Pagasa Administrator Nathaniel Servando also clarified during a press briefing that there is no summer in the country, and that there are only two seasons — wet and dry.

Filipinos have been wrongly referring to the warm-dry season as summer, he said.

Servando said the dry season will last until May, with temperatures expected to rise.

In the coming weeks, the days would be warmer and drier, as the moderate El Niño episode continues until May.

Pagasa said the retreat of the high pressure area over Siberia will further weaken the northeast monsoon.

At the same time, the strengthening of the North Pacific High will lead to a gradual shift in the wind pattern from northeasterly to easterly, resulting in higher temperatures over most of the country.

"These signify the end of the northeast monsoon and the beginning of the warm and dry season," Pagasa said.

Servando said the effects of El Niño, which were associated with extreme heat and drought, are also expected to bring drier conditions until May.

Pagasa advised the public "to take precautionary measures to minimize heat stress and optimize the daily use of water for personal and domestic consumption."

Dam water levels are expected to drop further in the coming months due to the combined effects of El Niño and below-normal rainfall.

Pagasa has predicted that the Angat Dam, the main source of water for Metro Manila and irrigation for neighboring provinces, will likely drop to 183 meters by May.

In the past, the water level at Angat had fallen to as low as 180 meters, Pagasa said.