Is the Serval Nocturnal?
The serval is a tall, slim and lightly built wild cat species found in Africa. In America, some people like to domesticate them. This is quite rare but they can be domesticated to a certain extent but in my view they do not make good pets.

Captive serval with white rabbit in mouth.
Is the serval nocturnal? The serval is usually described as a strictly nocturnal cat. However, this cat’s activity will depend somewhat on patterns of prey activity and also whether the cat is being disturbed by human activity. Often wild cat species modify their behaviour to avoid human activity to the point of becoming nocturnal or daytime hunters against their natural preferences.
Servals may also be less nocturnal in areas where there are many other nocturnal competitors. In one study, in an undisturbed area of the Ngorongoro Crater, servals mainly hunted in the early morning and late afternoon. Their peak of activity was for three hours during the night.
In cool cloudy weather it is not uncommon to find servals hunting at midday, and under these circumstances, the serval will usually find a shady spot to rest during the heat of the day between around 11 am and 4 am.
In other areas, servals mainly hunt at night. In the Rustenburg Nature Reserve, South Africa, two radio collared servals were mainly nocturnal. They were also active in a limited way in the early morning and late afternoon. In the Kamberg Reserve in Natal a study found that servals were also active at night. However, on overcast and misty days six servals moved around during the daytime as well.
In the Ngorongoro Crater serval hunting patterns were also affected by weather conditions. Servals tended to avoid hunting on windy days and they spent the day resting and waited until the winds subsided in the early evening. Windy conditions interfere with the cat’s ability to locate prey. It obscures the rusting noises made by rodents in grass (their main source of prey).
I hope this answers the question in the title.
Source: Wild Cats of the World page 144. ISBN-13: 978-0-226-77999-7