There are a number of factors that influence the frequency of flights.

Firstly, the number and frequency of flights will vary on a daily, weekly and yearly basis due to differences in airline schedules. The airlines schedule flights in response to consumer demand. This is particularly the case around Christmas, Easter, school holidays and Lunar New Year.

Secondly, the runway in use at any given time will also vary, largely due to the wind conditions. Each runway has its own set of flight paths, and each flight path will affect different areas. As the runway in use changes, the flight paths change, and so too do the areas affected by aircraft movements.

This chart shows the total number of flights each hour over the month, compared to the average for last year. Change the selected month to see how it has varied.