Phuket International Airport (VTSP/HKT) in the Kingdom of Thailand lies within a tropical monsoon climate zone and experiences hot and humid conditions throughout the year. The primary weather phenomenon affecting flight operations is thunderstorms, and understanding their seasonal occurrence patterns is essential for developing stable and reliable operational plans.
Topography and Climate
Phuket International Airport (VTSP) is an international airport located in the northern part of Phuket Island, a resort destination in southern Thailand. The airport lies within a tropical monsoon climate zone, with high temperatures throughout the year and daytime highs generally exceeding 30°C. September to October corresponds to the rainy season, while November to February is considered the dry season; however, convective precipitation typical of tropical climates can occur year-round. The primary weather phenomenon that disrupts flight operations is thunderstorms. These occur most frequently between 09Z and 18Z throughout the year, with a pronounced peak in activity between 11Z and 16Z.
Seasonal Weather Characteristics
・Spring (March–May)：April and May are the hottest months of the year. Thunderstorms accompanied by short-duration heavy rainfall peak from March to April. Thunderstorm activity is frequent between 08Z and 19Z, with the highest occurrence rates from 10Z to 15Z. In March, days with reduced visibility are relatively common, mainly associated with rainfall, with average visibility around 3,000 meters.
・Summer (June–August)：This period corresponds to the rainy season, though rainfall is generally short-lived and does not persist for long durations. Thunderstorms may occur at any time of day, but their overall frequency is lower than in other seasons. Days with degraded visibility are relatively frequent, primarily due to precipitation.
・Autumn (September–November)：September and October are characterized by high humidity and sultry conditions. In October, thunderstorms frequently occur between 11Z and 17Z, with a peak from 13Z to 16Z. In November, thunderstorms are most common between 09Z and 18Z, with the highest occurrence between 11Z and 14Z. Through October, the number of days with reduced visibility due to rainfall remains high.
・Winter (December–February)：Thunderstorms are most likely to occur between 12Z and 16Z in December, 11Z and 17Z in January, and 12Z and 16Z in February. Visibility reductions are mainly associated with rainfall, and conditions below 1,000 meters are typically short-lived.
Challenges in Operational Decision-Making
At tropical airports, operational decisions depend not only on whether thunderstorms will occur, but also on when their impacts are likely to begin and how long they may persist.
Even when thunderstorm potential is indicated, uncertainty in the exact onset timing and duration can complicate operational planning, making it difficult to determine the realistic impact window.
A clearer understanding of both the likelihood of thunderstorms and their expected impact period would support ground operations, departure sequencing, and resource allocation, helping airlines reduce unnecessary delays.
