Why isn't it raining?

Hint 1 of 12:

Haven't you heard some folk tales that explain how to create rain?

Hint 2 of 12:

Bernard will tell one of them to you if you look at the car in 1993.

Hint 3 of 12:

Washing a car makes it rain.

Hint 4 of 12:

Or in the past, washing a carriage makes it rain.  There's a carriage just
outside of the inn.

Hint 5 of 12:

All you need to do is wash that carriage, and it will rain.

Hint 6 of 12:

To clean a carriage, you need soapy water and a brush.  Everything you need
for this puzzle is available in this time frame.