Location, location, location. Or I should say: angle, angle, angle.
It's all in the angle at which the sun's rays hit the Earth. If the angle is less perpendicular, the energy of sunlight is spread out over a bigger area and heats less effectively.
As I calculate it, today (with the north pole tipped 19.6 degrees away from the Sun) one-third less energy is falling on a square meter of New England snow than on a square meter of Exuma sand.
Of course, other factors determine the weather too -- currents of wind and water, proximity to the sea, and so on. But the basic reason I'm down here all toasty warm and Tom is freezing is -- angle, angle, angle.