It's Tough To Be a Rain Man is an episode from 1979 anime series, 2005 anime series and its remake, based on the manga chapter with the same name.
Plot[]
Nobita's father is going to play golf, but Nobita's father is not in a good mood. Nobita and Doraemon are really puzzled. Doraemon thinks that Nobita's father doesn't like playing golf. Nobita says this is impossible, thinking that Nobita's father can play golf, but he is very poor. Doraemon uses "Trumpet of the Heart" to listen to Nobita's father's heart. It turns out that Nobita's father is called Rain Man by the minister. Doraemon takes out the "Rain Man Sunny Man Watch" and tests it on Nobita's father, and finds that the value of the meter is -8.5. Nobita is worried that it will rain, but Doraemon says that all he needs to do is let his father be with a powerful Sunny Man who can offset negative numbers. After going out, Doraemon and Nobita try their best to find Sunny Man. The two test Suneo, but find out that Suneo was Rain Man. The two go to measure Shizuka again, and when they see the value was +9, they said, "What a powerful Sunny Man." Shizuka says "It's a woman". The two test Gian again, and the value on the meter shows +10. Only then does Nobita realize that Gian is the person they are looking for. The next morning, Nobita's father goes to play golf. Gian is taken to the golf course by Nobita and the two and complained that there is nothing fun here. Doraemon tell Gian that the mountains are the best place to practice singing. Doraemon takes out "Karaoke Machine" and asks Gian to practice singing. Gian's singing voice is considered by his father's colleague to be the sound of a wild beast. Nobita's father makes a hole in golf, and the minister says that he plays beyond his level. Nobita's father quickly replies "Where", saying that Rain Man's suspicion is cleared. Gian sings 100 songs and his voice becomes hoarse. Nobita asks him to sing for a while, and Gian angrily drives Nobita and the others away. Dad and the minister look at the sky and exclaim, "The sky has changed." Nobita and Doraemon hurry to find Shizuka, but Shizuka is taking a bath. It starts to rain lightly. Doraemon opens "Anywhere Door" and sees Shizuka taking a bath again. At this time, the light rain has just stopped and the sky begins to clear up again. Shizuka throws the bath water angrily, and Nobita and Doraemon have to endure it for a while longer.