Source: Tafsir al-Ahlam al-Kabir (Ibn Sirin)
Rain in a dream is mercy from Allah Almighty, goodness, sustenance, and relief, if it is general everywhere and causes no harm. If the rain is specific to a certain house or village, it indicates worry and tribulation for the people of that place. Heavy rain like a flood indicates strife or an epidemic. Bathing in rainwater is repentance from sins, healing from diseases, and removal of worries. Rain of blood indicates bloodshed and wars.
Source: Ta'tir al-Anam fi Ta'bir al-Manam (Al-Nabulsi)
Rain indicates relief, fertility, prosperity, and payment of debts. If it is in its proper season, it is good and beneficial. If it is out of season, it is sickness and tribulation. Whoever sees himself drinking clear rainwater will attain goodness and knowledge. If it is murky, he will fall ill proportional to how much he drank. Rain that damages crops indicates the injustice of the ruler or a general affliction. Light rain is better than heavy.
Source: Al-Isharat fi Ilm al-Ibarat (Ibn Shahin)
Rain is interpreted as mercy, goodness, and blessing from Allah Almighty. If the rain is general and in its season, it is evidence of abundant sustenance and low prices. If the rain is very strong, destroying houses, it is a punishment from Allah or a great strife. Whoever sees the sky raining something other than water, if it is something beloved, it is good, and if it is disliked, it is evil and tribulation.