Although nobody besides Allah knows when the final hour is, there are some signs that will precede the Day of Judgement, according the Quran and Sunnah.

“O Prophet! The infidels ask you about the time of Qiyamah. So tell them that it’s knowledge is with Allah only.
Quran, Surah Luqman

Certain events are going to take place prior to the coming of the final hour. These events are known as the Signs of Qiyamah. All Prophets informed their people of the signs of the final hour. Our Prophet Muhammad ﷺ being the last and the seal of Prophets, knowing that the Last Day is to come upon this ummah, explained clearly and in considerable detail the signs of the final hour to the extent that sometimes he would lecture his companions all day on this subject.

‘The Prophet sat down on the pulpit after Fajr Prayer and began a deliver a long sermon until the time for Zohr prayer came. After saying the Zohr prayer, he again sat on the pulpit and began the sermon, which continued till Asr prayer. After the Asr prayer, he resumed the sermon for so long that the sun set. He related whatever happened in the past and also related in detail whatever is to happen in the future. Those amongst us who had good memories retained many things.’
Narrated by Abu Zaid (Muslim)

The signs of the final hour can be divided into two categories:

1) Minor signs

Minor signs are events of normal nature prophesised by our Prophet Muhammad ﷺ to take place before Qiyamah, such as:

  • The consumption of alcohol
  • Lifting of knowledge and prevalence of ignorance
  • Immorality

The majority of the minor signs have already appeared, while some are occurring right now, and some will appear with major signs. A more thorough list can be found here

2) Major signs

Major signs are events of extraordinary nature prophesised by Prophet Muhammad ﷺ to take place before Qiyamah, such as the events mentioned in the following hadith.

Narrated by Hudhaifa ibn Usayd that Prophet Muhammad ﷺ said, ‘The last our will not arrive till you have seen ten signs. He Peace and blessings be upon him then mentioned:

  • The Smoke
  • Dajjal
  • The Beast
  • Rising of the Sun from the place of it’s setting
  • The Descent of Prophet Isa (Jesus)
  • Ya’juj Ma’juj
  • Three Landslides: one in the East , one in the West and one in the Arabian Peninsula
  • A Fire would spread from Yemen and drive the people to their place of gathering.’

(Muslim)

More information on each Major Sign:

Major Sign: Physical Signs of the Day (The Smoke, The Landslides, The Fire)
Major Sign #1: The Mahdi
Major Sign #2: The Dajjal (Anti-Christ)
Major Sign #3: The Return of Prophet Isa (Jesus)
Major Sign #4: Ya’juj and Ma’juj (Gog and Magog)
Major Sign #5: The Beast