Short answers, pulled from the story.
John Lennon described the song Rain as being about people moaning because they do not like the weather. He stated this in an interview where he discussed the lyrical themes of the track released on the 30th of May 1966.
The Beatles began recording Rain at EMI Studios in London on the 14th of April 1966. They completed the track on the 16th of April with a series of overdubs before mixing on the same day.
Engineer Geoff Emerick altered the sonic texture by taping the backing track faster than normal so that when played back slightly slower it had a radically different tonal quality. Lennon recorded his lead vocal with the tape machine slowed down to make his voice sound higher when played back.
One film shows the band walking and singing in the gardens and conservatory of Chiswick House in west London while another two clips feature the band performing on a sound stage at EMI Studios on the 19th of May. Authors Mark Hertsgaard and Bob Spitz recognized the 1966 promos as the first examples of music videos.
Petula Clark covered Rain on her 1966 album I Couldn't Live Without Your Love and Shonen Knife covered the song on their 1991 album 712. U2 played the song throughout many of their tours usually during outdoor concerts when it started to rain.