How does weather affect the use of public transport in Berlin?

The effect of weather on public transport usage in Berlin is analysed. The number of single and day tickets sold is used as a proxy for the number of occasional public transport users. Analysing more than three years of hourly ticket sale data, it is shown that the most important factor influencing ticket sales is temperature. Temperatures below −5 ^° C lead to an increase in ticket sales by up to 30% on working days, while on hot days (> 28 ^° C) passenger numbers drop by up to 5%. Precipitation increases the number of sales on working days by up to 5%. On weekends, the lowest ticket-sale numbers are associated with wet and either very cold or very hot conditions. Another factor influencing ticket sales is sunshine duration, while wind and snowfall do not seem to play a role for ticket sales in Berlin. It is demonstrated that it is possible to predict ticket sales depending on date, time and weather conditions using a statistical model. On designated public transport routes the effect of weather on passenger numbers can be much stronger than the district average. This is shown for the example of a bus route to a public beach. With each degree of temperature increase, passenger numbers on this line go up by approximately 30%.