To add a little winter magic feeling on your Desktop is DesktopSnowOK the right program.

DesktopSnowOK is a lightweight portable Windows program
for 5 or more snow flakes on your windows desktop.

DesktopSnowOK does not have to be installed and can be executed easily from the desktop,
and can be carried on a small usb-stick or other memory device.
It's a small fun program for all Windows-NT systems.

:::: Features :::::
# Very Small
# Low CPU usage
# 5-64 snow flakes
# Adjustable speed
# Several flakes textures (bitmaps)
# Optional transparency
# Optional deactivation by mouse movement or keyboard input
# Optional translation feature
# Portable

You can try this freeware and if you not satisfied, you can delete it quickly.