Evaluation of Visibility Conditions at Port Harcourt International Airport for Aviation Safety

Meteorological visibility is a critical parameter governing aviation safety, particularly at airports located in regions with high fog and haze frequency. This study evaluates surface visibility conditions at Port Harcourt International Airport in Rivers State, examining data from the airport's meteorological observation unit covering 2020 to 2024. Hourly visibility reports were classified according to International Civil Aviation Organization (ICAO) categories, and frequencies of low visibility events were analyzed across seasons, months, and times of day. Synoptic conditions associated with visibility reduction were identified using archived upper-air and surface analysis charts from NiMet. Results indicate that Port Harcourt airport experiences low visibility events below 1,000 metres on an average of 38 days per year, with peak frequency in the early morning hours of November through January, attributable to radiation fog formation under clear skies following dry-season onset. Occurrences of below-600-metre visibility, categorized as Category II conditions requiring instrument landing systems, account for 11 percent of all low visibility events. The study identifies a direct relationship between reduced visibility frequency and flight delay statistics obtained from the Nigerian Civil Aviation Authority (NCAA). Recommendations include upgrading the airport's automatic weather observation system (AWOS) and training meteorological staff in Category II/III weather phenomena interpretation. Keywords: visibility, aviation meteorology, Port Harcourt, fog, ICAO.