From My Personal Grimorie: Cold Conjuring

As I write this, we've entered the late Autumn. Gone are the bright riot of color seen in the earliest days after Mabon. Now that the trees have shed their leaves, all that remains are their stark, gray skeletons. When the wind blows at night, the wooden bones clatter, and the crisp brown leaves dance in circles. These are the evenings when I settle in with a cup of hot tea to ponder and read by candlelight: I have entered the Place of Deep Indwelling, a palpable place when I feel drawn down, down the spiral of space into the most ancient of times. The cold outside is oddly exhilarating as it contrasts against the warm air inside. I find that some nights, when I cannot sleep, opening a window just enough to allow a finger of cold air curl in relaxes me.

Occasionally, I also do this when I meditate, because I find the shock of cold helps bring clarity quickly when I'm attempting to empty my mind. The primal rawness of cold is a wonderful focusing tool.

If the weather has dipped below freezing and there are icicles, I gather a few clean, fragile points to use in magickal workings during ritual. I suppose they could be stored in the freezer until ready to use, but I have always taken them just before I cast my circle, when I believe they are most potent. I have used icicles in place of quartz crystals with very satisfactory results. Place the ice points on a pretty dish or ornamental tray so that the top of your altar isn't marred as they melt. Depending on the nature of the spell, the water resulting from the melted icicles can be bottled and saved for use later, or poured outside and returned to the earth.

If you know anything about the basics of spell work, then you are aware of the result of putting a poppet or spell bag into the freezer. Placing these things outside ( selectively) will have the same result.

I have found that a bowl of snow has many uses as well: projecting pure, white energy into the bowl while the snow melts will provide a naturally consecrated amount of blessed ("holy") water to be used in the future.
It can be added to any spell that calls for spring water; or used to anoint yourself or ritual items. The water left from melted snow is naturally powerful because it already contains the energies of water, air and earth. It is imbued with whatever minerals it has come into contact with during it's formation in the atmosphere. Snow also has its own particular form of crystal energy. A bowl of  snow can be used for scrying (look for shapes to appear as it melts. Water left in the bowl can also be used for scrying. I have gathered snow in a metal bowl, allowed it to melt, then put it outside to re-freeze and used the surface of the ice for a different version of scrying (Metal or freezable plastic is best. Don't use pottery or glass that will crack or shatter). Droplets of condensation from melting snow that has been heated is especially good to use in ritual washes for the body, tools, or the altar. ( A lovely winter floor wash can be made from heating snow until it melts, then adding pine needles, a pinch of cinnamon, and a drop of lemon or lime. I don't recommend using orange juice as it can leave a sticky residue.) In this way, either snow or ice can be used as the liquid in which to suspend herbs for aromatherapy. I do not recommend the use of either snow or ice in anything you will consume/drink, because they could contain harmful impurities if taken internally. If you do use snow/ice in this way, be sure of the safety of your source.

Finally, did you know that snow can be used to make a figure to be used in the same way as a wax candle?
You don't have to have any artistic talent to do this: it's a little like making a poppet out of snow. Mold the figure by compacting snow roughly into any form you want, visualizing your desire while doing do, or place herbs, etc inside the core of the figure as it is being made. Fix it with your intention, or incorporate it into your spell work. The magick is released as the figure melts on its own.