For the longest hours of sunlight during the summer, you want to move towards the poles (away from the equator). Above the Arctic Circle, like in parts of Sweden or at the North Pole, for example, the sun never sets from June to July. However, in return, the sun never comes out at all for several months in winter.

The reason for this is because Earth is tilted 23.5 degrees away from its axis of rotation. If there were no tilt, everywhere on Earth would receive 12 hours of daylight and 12 hours of night every day, regardless of how close or far to the Equator. Because of the tilt, however, the time each point on Earth spends in light and in shadow each day is unequal - areas pointed toward the sun get more hours of daylight while areas pointed away from the sun get fewer.

The length of the daylight hours is the most important factor in determining the seasons - summer has longer days and is thus hotter, while winter has shorter days and is thus colder. The distance from the Equator (latitude) determines how unequal the hours of daylight and night are as the seasons change. Areas near the Equator, between the Tropics of Cancer and Capricorn, have little difference in daylight hours between summer and winter. This is why the changes in seasons in the tropics are mild. Areas further from the Equator have more and more difference in daylight hours, and thus have more distinct season.Above the Arctic (or Antarctic) circles, these extremes lead to unending summer days and winter nights.

This website provides more information on seasons and daylight hours: