Context

October is usually the transition month of the monsoon season in the Philippines. From southwest monsoon (Habagat) during June-September, it transitions to northeast monsoon (Amihan) during October or November.

Purpose

I created this wind rose diagram to visualize the change in the wind direction over the months of September-October recorded in our Parañaque City, Metro Manila, Philippines Automated Weather Station. From winds usually coming from the west during September and on early weeks of October, there was a noticeable change in the direction during the latter part of October.

How to Read

The yellow polar bars represent the occurrence of the wind coming from the direction these point to. The length of the polar bars represents the frequency of that occurrence. The longest bar represents the majority of the recorded wind direction. The visualization presents the wind direction recorded at each day, from September 6, 2023 until November 1, 2023.

Insights

1. Before October 9, the station recorded the wind generally blowing from the west, except for some days like during September 16-21. This is expected as the southwest monsoon was still active during these days.
2. On and after October 9, the station already recording wind generally blowing from the east. This could be an indicator that the southwest monsoon is getting weaker and eventually northeast monsoon is coming in.
3. On October 12, DOST-PAGASA announced the termination of the southwest monsoon due to its weakening status. Read more here: Termination of the Southwest Monsoon. This termination is in agreement with what was observed in our weather station. On and after October 12, you would see that the wind generally blows from the east with just rare occurrences of winds blowing from the west.
4. Eventually on October 20, DOST-PAGASA announced the onset of northeast monsoon as they've saw the presence of "strong northeasterly winds that have prevailed over Northern Luzon". Read more here: Onset of Northeast Monsoon.

Notes

The said weather station is an amateur one and the analyses done here are only for educational and preliminary inspection purposes only. For official data, please contact DOST-PAGASA or visit their website here.

The Python script that created the said wind rose diagram could be viewed here.