Winter
Winter brings the shortest days and the least daylight ... in either hemisphere.
Summer
Earth's rotational axis is tilted. Thus as it orbits the sun the length of the day varies. In either hemisphere the daylight hours are shortest during the winter season, and longest in the summer. The length of the full day/night cycle does not vary by season, but is affected (very minutely) by other factors.
There is always more daylight during the summer months, which is what makes them summer months. Note, of course, that when it is summer in one hemisphere, it is winter in the other. Total daylight on earth overall varies little from day to day or season to season.
It is called the "Equinox" and occurs during the winter season.
This was created for farmers to extend the daylight hours during peak growing season.
In Washington during the summer, there are about 15-16 hours of daylight. This can vary slightly depending on the specific day of the summer season.
Though mainly nocturnal (during the night), in the rainy season, they have sometimes been seen during daylight.
Violets will bloom during daylight hours when in season.
Summer
From the December solstice to the March equinox is the shortest season -- 88.99 days.This is winter in the northern hemisphere, summer in the southern hemisphere.From the June solstice to the September equinox is the longest season -- 93.65 days.
In January, there are typically more hours of darkness than daylight in the Northern Hemisphere due to the winter season. Conversely, in the Southern Hemisphere, there are more hours of daylight than darkness during January as it is summer in that part of the world.