Using the AWOS（Automated Weather Observing System）automatic observation data at Maotai Air‐ port from 2017 to 2023，ERA5（ECMWF Reanalysis v5）reanalysis data，and the ETOPO2v2 topography data provided by the National Oceanic and Atmospheric Administration（NOAA）of the United States. Using methods such as weather analysis，statistical analysis，and diagnostic analysis，this study investigates the characteristics and influencing factors of low visibility weather at airports，and employs the HYSPLIT backward trajectory model to trace the sources of water vapor in low visibility weather. The results show that Maotai Airport has higher humidity throughout the year，with obvious characteristics such as low temperature，high humidity，and low wind speed in autumn and winter，which is more conducive to the formation and maintenance of low visibility weather. Low visibility weather occurs at the airport every month of the year，with the number of low visibility days being higher than average from October to February of the following year and in late spring and early sum‐ mer. The frequency of low visibility weather gradually increases from dusk throughout the day. In spring，the frequency reaches its highest point from 06:00（Beijing Time，same as after）to 08:00 in the morning，in summer and autumn from 05:00 to 07:00，and in winter from 03:00 to 05:00. In addition to low wind speeds，the main factors affecting low visibility weather include terrain，circulation background，inversion，temperature advection，and water vapor conditions. When low visibility weather occurs，the prevailing wind direction at the airport is WNW，which is closely related to the terrain of the Chishui River Valley and the activity of cold air. In spring， autumn and winter，the upper air level above the airport is mainly affected by the westerly airflow，and the lowlevel airflow from the north and the south converge over the Yunnan-Guizhou Plateau，resulting in the Kunming quasi-stationary front. Frontal inversion is beneficial for water vapor to accumulate near the ground and reach saturation. Low visibility weather at the airport typically appears in the cold zone behind the frontal zone. In summer，the temperature inversion over airports is mostly radiation inversion，and low visibility weather is mainly radiation fog. The HYSPLIT water vapor tracking results show that there are two main sources of water vapor at an altitude of 1500 meters during low visibility weather，namely the Bay of Bengal on the south side of the Qing‐ hai-Tibet Plateau and the Chishui River Valley in the northwest of the airport；the water vapor at an altitude of 3000 meters mainly originates from the Bay of Bengal.