It's getting dark; why?

September is the month where we lose the most daylight from beginning to end, with the sun rising around a half hour later, and setting around an hour later. On the flip side of that, March is the month that we gain the most sunlight, gaining about an hour in the morning, and around 30 minutes at night. Now there are a couple big reasons we don’t feel this switch as much, first the biggest gain is at the beginning of the day, and not too many people wake up to watch the sunrise, more people are awake for the sunset. The second reason is because of daylight saving time, with us springing forward in the middle of the month time gets all out of balance. And by the time you get used to it, you don’t notice that you’ve gained daylight.

The earth’s orbit is not a perfect circle with there being points where the earth is closer and farther away from the sun. Now of course the earth’s tilt gets specific places on the earth further away from the sun during different season, but with the path of the earth's orbit being just a little off kilter, there would be times that we would be actively moving further away from the sun. One of those times is September. Combining the tilt and the slight movement away from the sun creates the faster loss in daylight. This can be best seen on a sun chart, called an analemma, which measures the angle of the sun. Using trigonometry, the ancient Greeks were able to figure out that the orbit wasn’t a perfect circle, or else this would be a perfect figure 8 shape.