Praise be to Allah.
Shaykh Ibn ‘Uthaymeen said:
The time for stoning Jamrat al-‘Aqabah on the day of Eid, for those who are able to do it, is from sunrise on the day of Eid, and for those who are weak and unable to cope with the crowding – women and children – the time is from the end of the night. Asma’ bint Abi Bakr (may Allaah be pleased with her) used to watch out for moonset on the night of Eid (the night before), and when it had set she would go from Muzdalifah to Mina and stone the Jamrah. The end of the time for stoning the Jamrah is sunset on the day of Eid. If there is too much crowding and a person is far away from the Jamrah and wants to delay it until night time, there is nothing wrong with that, but he should not delay it until dawn on the eleventh of Dhu’l-Hijjah.
With regard to stoning the Jamaraat on the days of al-Tashreeq – the 11th, 12th and 13th of Dhu’l-Hijjah – that starts after the sun has passed its zenith – i.e., midday when the time for Zuhr begins – and lasts until nighttime. If it is too difficult because of overcrowding etc, there is nothing wrong with stoning the Jamaraat at night, until dawn. It is not permissible to stone the Jamaraat on the 11th, 12th and 13th before midday, because the Prophet (peace and blessings of Allaah be upon him) did not stone them until after midday, and he said to the people: “Learn from me your rituals (of Hajj).” The fact that the Prophet (peace and blessings of Allaah be upon him) delayed stoning the Jamaraat until this time, even though it was very hot, and did not do it earlier in the day, when it is cooler and easier, indicates that it is not permissible to stone the Jamaraat before this time. This is also indicated by the fact that the Prophet (peace and blessings of Allaah be upon him) used to stone them from the time when the sun passed its zenith before he prayed Zuhr. This indicates that it is not permissible to stone the Jamaraat before the sun passes its zenith, otherwise doing that would be better so that one could pray Zuhr when its time began, because it is better to pray when the time for that prayer begins. The point is that the evidence indicates that stoning the Jamaraat on the days of al-Tashreeq is not permissible before the sun has passed its zenith.
Fataawa Arkaan al-Islam, p. 560.
He also said:
Stoning Jamrat al-‘Aqabah on the day of Eid ends when dawn comes on the 11th and starts from the end of the night for the weak and others who cannot cope with the crowding.
With regard to stoning it (Jamrat al-‘Aqabah) on the days of al-Tashreeq, as with the other two Jamrahs it is to be done from when the sun passes its zenith (the beginning of the time for Zuhr prayer) and ends at dawn the following day, unless it is the last of the days of al-Tashreeq, in which case stoning should not be done during the night because that is now the 14th of the month. The days of al-Tashreeq end at sunset on the 13th. However stoning during the day is better unless – because of the large numbers of pilgrims and their thoughtless attitude towards one another – one fears death, harm or unbearable hardship, in which case it is permissible to stone the Jamaraat at night and there is nothing wrong with that. If a person stones them at night even though he does not fear these things, there is also no harm in that, but it is better to be on the safe side in this matter and not stone them at night unless there is a need to do so.
Fataawa Arkaan al-Islam, p. 557-558.