Dude,
An easy way of working out daylight length is to check weather websites or in the newspaper weather forecasts where they always tell you sunrise and sunset times. Then, judging by how much cloud/rain you have in a day, you can work out roughly how much daylight hours/night hours you've had. On a cold, overcast day sunrise will be later and sunset earlier but it's the average that counts - I try and work mine out over a weekly period.