Windsor is not 5 minutes outside of Detroit. Windsor sits directly across the Detroit River from Detroit, Michigan. Outside is not a term used for a city that is directly next door.
The rainmaker is arrested for building a fire in a Manhattan park to induce rainfall. However making it rain in the city would be a waste since the water would simply drain into the rivers. If he wanted to save the city from drought, then he should have concentrated his efforts to the north, where the city's reservoirs are located.