Can the change in the # of hours of daylight over the course of a year help (it doesn't have to be the only factor) explain the differences in temperature between summer and winter?

Yes.

Explanation:

The duration of hours of the day is longer during the summer and shorter during the winter and this influences the temperature in these two seasons. As the day is longer in the summer, it means that the hemisphere that this summer has more exposure to the sun and therefore has higher temperatures. The opposite happens in the winter, as there is less exposure to the sun, due to the shorter day, which can help in decreasing the time.