1. Wet dreams during the day of fasting do not invalidate the fast, according to the agreement of scholars, because there is no intention there.
2. Involuntary vomiting: because the Prophet said: “Whoever is overpowered by vomiting (while fasting) does not have to make up for that day.”
3. This also applies to anything that enters the throat without one's choice such as dust, flies or other things that are hard to avoid. This does not invalidate fasting because there is no intention or deliberateness, and such a person is not addressed by the Sharee‘ah command; Allah The Almighty Says (what means): {Our Lord, do not impose blame upon us if we have forgotten or erred.} [Quran 2:286] The Prophet said: “Allah The Almighty has pardoned my Ummah (nation) for mistakes, forgetfulness and what they are coerced to do.”
4. Unintentional bleeding such as nosebleeds, bleeding, wounds and so on. This does not break the fast because there is no intention or willingness present.
5. Eating or drinking out of forgetfulness does not invalidate the fast because the Prophet said: “Allah The Almighty has pardoned my Ummah for mistakes, forgetfulness and what they were coerced to do.” He also said: “If any one of you forgetfully eats or drinks while fasting, he should complete his fast, for it was Allah who has fed him and given him something to drink.”
6. Whoever eats while having doubt whether dawn has broken or not should not make up for this day because the fundamental ruling is the continuation of night until it is proven that dawn has broken.
7. Waking up in a state of Janaabah (post sexual-intercourse impurity) due to a wet dream or sexual intercourse at night does not invalidate fasting. Sometimes there is not enough time to perform Ghusl (ritual bathing) before Suhoor (the pre-dawn meal) or the break of dawn. No day should be made up for this day because it is narrated that, “The Messenger of Allah sometimes used to be in a state of Janaabah at the time of Fajr (dawn), so, he used to perform Ghusl and fast.” [Al-Bukhari & Muslim] In another Hadeeth, the Prophet replied to a man who asked him about this case saying: “Me too. The prayer (Fajr) is called while I am in a state of Janaabah, so I fast.” There are many texts proving this and scholars unanimously agree upon it.
8. If a person thinks that the sun has set because of clouds or the like and breaks the fast and then it turns out that the sun has not set, he should resume fasting and does not have to make up for this day . This is the opinion chosen by a group of scholars including Shaykh Al-Islam Ibn Taymiyyah who said, “If the fasting person eats at the time of sunset thinking that the sun has most likely set and then the sun appears and he stops eating and resumes his fast, his ruling is that of the person who eats out of forgetfulness. It is narrated in an authentic Hadeeth that people broke their fast during the lifetime of the Prophet then the sun appeared again… the Hadeeth did not mention that they were commanded to make up for that day. If this had happened, this news would have been spread just as the incident of their breaking their fast was narrated. Since it has not been narrated that they made up for that day, then, (we can safely assume) that they were not commanded to do so.” It is narrated in an authentic report that once ‘Umar Ibn Al-Khattaab, may Allah be pleased with him, broke his fast during the day upon thinking that the sun had set, then, it appeared again. He said, “We should not make up for this day because we did not incline to sin.” Shaykh Al-Islam said, “This opinion is stronger in terms of evidence and reasoning and very close to the evidences of the Quran, Sunnah and analogy.”