Short answer
Yes. The Prophet ﷺ fasted more in Sha'ban than in any month apart from Ramadan, so fasting much of Sha'ban is a sunnah. In the Hanafi school you may fast in its second half too; only the last day or two before Ramadan are disliked unless they are your habit. The Shafi'i school discourages starting new voluntary fasts after mid-Sha'ban.
Fasting in Sha'ban is mustahabb. Fasting the day of doubt (30 Sha'ban) with the intention of Ramadan, or a day or two before Ramadan to 'welcome' it, is makruh; a habitual fast such as Monday is fine. The hadith on not fasting after mid-Sha'ban is read as advice for those it would weaken.
Other madhhabs
- Shafi'i
- Starting voluntary fasts after the 15th of Sha'ban is forbidden unless it is your habit, a qada or vow, or joined to fasts from the first half.
Explanation
Aisha said that she never saw the Prophet ﷺ fast more in any month than in Sha'ban. Usama ibn Zayd asked him why, and he explained that it is a month people neglect, between Rajab and Ramadan, and that in it deeds are raised to Allah, and he loved his deeds to be raised while he was fasting.
How to fast in Sha'ban:
- Fast as many days as you can, such as Mondays and Thursdays and the white days.
- It is a good time to finish any Ramadan fasts you still owe. See making up missed fasts.
- Avoid the last day or two before Ramadan unless it is your normal fast. See fasting the day before Ramadan.
The second half. Abu Dawud records that the Prophet ﷺ said not to fast once Sha'ban is half over. The Hanafi scholars, and many others, reconcile this with his own fasting in Sha'ban by reading it as advice for people whom fasting would weaken before Ramadan. The Shafi'i school takes it as a prohibition on starting new voluntary fasts in the second half.
The 15th of Sha'ban. A hadith in Ibn Majah tells people to fast the day after the 15th night, but its chain is very weak. Hanafi scholars such as Mufti Taqi Usmani say you may fast that day as one of the white days and of Sha'ban, but should not believe it is a fixed sunnah. See Shab-e-Barat.
The evidence
Sahih al-Bukhari 1969
Sahih... وما رأيته أكثر صياما منه في شعبان ...
"And I never saw him fast more in any month than in Sha'ban."
Fasting much of Sha'ban is the sunnah.
Sunan an-Nasa'i 2357
Grading to be checked... ذلك شهر يغفل الناس عنه بين رجب ورمضان ...
"That is a month people neglect, between Rajab and Ramadan."
The reason he gave for fasting in Sha'ban.
Sunan Abi Dawud 2337
Grading to be checked... إذا انتصف شعبان فلا تصوموا ...
"When Sha'ban is half over, do not fast."
The basis of the Shafi'i view; the Hanafi school reads it as advice for those it weakens.
Where the ruling is recorded
- al-Fatawa al-Hindiyya, Kitab al-Sawm, chapter on what is desirable and disliked in fasting. Fasting in Sha'ban is among the desirable fasts.
- al-Hidaya, Kitab al-Sawm, section on the day of doubt. Fasting the day of doubt with Ramadan's intention is disliked; a voluntary fast that matches one's habit is fine.
- Minhaj al-Talibin, Kitab al-Siyam, chapter on voluntary fasting. The Shafi'i prohibition of voluntary fasting after mid-Sha'ban without a cause.
Checked by our team. For a more accurate answer to your own situation, consult a scholar. Quran translation by Sahih International. Hadith Arabic from the standard editions of the six books and the Muwatta, with gradings as recorded there; the English is our own rendering. Spotted a mistake? Tell us.