By Ma. Cristina Arayata | Philippine News Agency
The upcoming onset of the northeast monsoon or “amihan,” season may bring cooler days ahead and longer nights due to the equinoxes, the head of the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) said Monday.
PAGASA Administrator Nathaniel Servando said Sept. 22 is the autumnal or fall equinox, when neither the Earth’s pole is tilted.
“It marks the beginning of the Earth to tilt away from the sun, and just the beginning of longer nights and shorter daytime,” he told the Philippine News Agency.
He added that meteorologically, Sept. 22 marks the end of summer in the northern hemisphere and the start of autumn season.
PAGASA’s recorded sunrise on Sept. 22 was 5:45 a.m. and sunset at 5:52 p.m.
Servando said sunrise on Monday is at 5:45 a.m. and sunset at 5:51 p.m., a minute earlier from the previous sunset.
Those in the equator had an equal daytime and nighttime on Sept. 22, he said.
The Philippines, which is in the northern hemisphere, could expect the start of the winter season on Dec. 21 (winter solstice) until March 20 (vernal or spring equinox) or the start of spring.
“The longest nighttime will be on Dec. 21, when either of the Earth’s poles reaches its maximum tilt (23.5 degrees) away from the Sun,” Servando said.
Servando said that on Dec. 21, the day will be shorter by about 1 hour and 44 minutes.
For comparison, he said that last June 21, sunrise was at 5:28 a.m. and sunset was at 6:28 p.m.
On Dec. 21, sunrise will be at 6:16 a.m. while sunset will be at 5:32 p.m.
“Then the Earth’s tilt will move towards zero degree again on March 20 (during vernal or spring equinox), and daytime and nighttime will be equal again,” he said.
Meanwhile, Servando said the public could also look forward to cooler temperatures in the coming days due to the “amihan” season.
“In the coming days, the winds will be colder due to the shift from ‘habagat’ (southwest monsoon) to ‘amihan’,” he said.
However, there is no indication yet to terminate “habagat” as the prevailing weather system, Servando said.
“But normally, the onset of ‘amihan’ season falls between the last week of September to first week of October. It varies,” he said.
The onset of “amihan” season was declared on Oct. 20, 2023, and was terminated last March 22.