Cheetahs hunt mainly during the daytime but it depends on where they are. In the Sahara where it gets very hot they do most of their hunting at night and in the hours after daybreak. One website (BBC) states that their night vision is hardly any better than ours which is unusual for a cat if this is true. If it is then it would partly explain why cheetahs like to hunt in the daytime. It is also said that in the early hours lions are less likely to be active. Leopards, hyenas and lions are a threat to the cheetah. They are larger and more aggressive and they kill adult cheetahs and cubs and steal their kills. The cheetah is relatively retiring and timid so it keeps its distance.
In the Serengeti, cheetahs prefer to hunt slightly later in the morning and earlier in the afternoon than hyenas or lions as a way of avoiding these larger and more aggressive predators. In the Masai Mara region of south-western Kenya, they are mainly active between 7:30 AM and 10 AM and then later on in the day they are more active between 4:30 PM and 7:30 PM. Normally cheetahs rest during midday.
In the Serengeti and in Namibia, they have been seen hunting at night. The information that I have is rather sparse on their night-time activities. During the night, it is common for family groups of cheetahs to spend the time resting in open grassy areas. They appear to remain in the same place all night because they are seen in the same place in the morning. Juvenile groups and male cheetahs sometimes travel during the night.
References:
- The effects of human activities on cheetahs in the Mara region of Kenya by DA Burnley written in 1980 as their masters thesis at the University of Nairob.
- The Serengeti lion by GB Schaller published by University of Chicago press 1972.
- Notes on the foraging habits of cheetah by P Stander in 1990.
The references are taken from Wild Cats of the World by Mel and Fiona Sunquist. Buy the book if you want to learn about the wild cat species.