By using the hourly visibility and runway visual range (RVR) observation of nearly 20 years (1996〖CD*2〗2013), the annual, seasonal, and daily variation characteristics of low visibility (＜800 m) and low RVR (＜550 m) in the Shanghai Hongqiao International Airport are analyzed. Results show that low visibility appeared more frequently than low RVR in almost all years except 2002 From 1996 to 2013, the numbers of both low visibility and low RVR events showed decreasing trends by the rate of 57 times/year and 26 times/year, respectively. The low visibility and low RVR appeared most frequently in December, while the least in September. For both, November to February was the high frequency period and May to September is the low frequency period. As for daily variation characteristics, low visibility and low RVR events occur usually in 19:00〖CD*2〗01:00 UTC with the peak at 23:00 UTC. During the night, the appearing rates of low visibility are greater first, and afterwards the impaction of low RVR events becomes prominent gradually from midnight to early morning. Along with the decreasing of visibility, the number of low visibility events decreases at first then increases. Meanwhile, the number of low RVR events is relatively greater in the ranges of 150〖CD*2〗200 m and 0〖CD*2〗50 m.