The hour of sunlight is approximately sinusoidal. Changing time is approximating the sinusoid with a square wave. It's not as smooth as it could be, but smoothi

The hour of sunlight is approximately sinusoidal. Changing time is approximating the sinusoid with a square wave. It's not as smooth as it could be, but smoothing it out would cause more accounting problems than it would solve. It is also easier to manage than having schools and businesses change their hours in winter, which is the other way to approach the solution. If you want a smoother transition you are fully in control of that.