Corrected entry: When Marty gets the Western Union letter from 1885 Doc it is raining but if this is at the same moment we get the recap of the 1955 Doc from the first film on the clock tower it wouldn't be raining, just thunder and lightning.
jbrbbt
17th May 2022
Back to the Future Part II (1989)
Correction: Also, different areas. It can be pouring rain in 1 spot, while sunny just a few feet away.
Correction: A great observation, but rain can last anywhere from a few minutes to a few hours so a rain shower at this time is not impossible.