Climatological Normals of General Santos City, South Cotabato, Philippines (1991–2020): Analysis of Temperature, Rainfall, Humidity, and Atmospheric Parameters

This paper characterizes the climatological normals of General Santos City, South Cotabato, Philippines, for the 1991–2020 World Meteorological Organization (WMO) standard reference period, using published data from the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA). The analysis is descriptive in scope and is based on the twelve-monthly normal values (n = 12) derived by PAGASA from the underlying 30-year observational record for the General Santos synoptic station. Because daily and monthly observations were unavailable, trend, anomaly, and extreme-value analyses were not performed. Rainfall, maximum and minimum temperatures, relative humidity, vapor pressure, dew point, mean sea level pressure, prevailing wind direction and speed, cloud amount, and thunderstorm and lightning frequency were summarized using descriptive statistics, seasonal grouping, diurnal temperature range (DTR) computations, and Pearson correlation analysis. The station records an annual cumulative rainfall of 958.1 mm distributed across 106 rainy days. June is the wettest month (101.9 mm), whereas February is the driest (53.0 mm). The mean annual temperature is 27.9°C, with the highest monthly maximum occurring in April (34.3°C) and the lowest in July and August (31.7°C); the annual mean DTR is 9.75°C. Because the correlations were computed across the twelve-monthly normal values rather than interannually, they reflect seasonal covariation rather than interannual or long-term relationships: rainfall covaries positively with relative humidity (r = 0.91) and negatively with mean temperature (r = −0.77). Prevailing monthly wind direction shifts from northeasterly during the dry season (December–March) to southerly during the wet season, consistent with the documented Philippine monsoon reversal. These results establish an updated station-level climatological baseline for General Santos City that may support subsequent work in agricultural planning, disaster risk reduction, and climate vulnerability assessment in the SOCCSKSARGEN region.