Although the equinox is often described as the day when day and night are equal, they are not perfectly balanced. This is due to two factors: the Sun's size and atmospheric refraction. The Sun is not a single point but a disk, so it takes time for the entire disk to rise and set, adding a few extra minutes of daylight. Additionally, Earth's atmosphere bends sunlight, making the Sun appear above the horizon even when it is technically below it. These effects combine to make the day slightly longer than the night during the equinox.