I notice it anytime of the day. Is it more blue at dusk?

Here is a link that might be useful: Blue Snow Shadows

Ken, I would love to go outside to take photos of blue shadows in the snow, but we have no snow. You are right, the shadows are blue because they are lit by reflected light, mostly from the blue sky.

If you can set white balance (WB) on your camera, try taking the snow scene with different WB settings to see if one gives you a result you like, rather than letting the camera choose with automatic WB. For example, try setting WB to the sunny icon.

Some example WB settings and corresponding color temperatures on the kelvin scale (in order of warm to cool) are: tungsten - 2700K, sunlight - 5500K, cloudy - 6500K, shade 7500K.

Was, light is especially blue right after the sun has set. This is called "the blue hour". The period right before sunset is referred to as "the golden hour" or "the magic hour".

Here is a link that might be useful: For golden & blue hours at your location, enter address, click on SEARCH FOR ADDRESS, then on GENERATE TABLE

SNOW??? That would require moisture to fall from the sky.......

mark