Cities that experience the least variation in the length of daylight throughout the year are typically located near the equator. Places such as Quito (Ecuador), Nairobi (Kenya), and Singapore experience minimal fluctuations in day length, with daylight lasting about 12 hours each day year-round.
In contrast, cities located at higher latitudes, such as those in Canada or northern Europe, experience significant variations in daylight due to the tilt of the Earth's axis, with long summer days and very short winter days.
If you have specific city options you want to consider, please provide them, and I can help identify which one experiences the least variation in daylight.