The key to writing a descriptive passage about any topic is to think about the adjectives and adverbs that can add to the detail in the reader's mind as you describe your topic.
In thinking about a winter day, start by deciding what is happening. Is it a bright, sunny day with sunlight making the snow sparkle with a blinding brightness while drips of water plop off the melting icicles onto the sidewalk below? Or are you describing a stormy day, with the wind howling, snow blowing sideways through the air, and the cold cutting through coats and scarves and mittens like a frigid knife?
You could go on to describe the activities of people or animals in response to whatever weather you have established. Again, the key is to decide what you want to have happening, and then think about how you can add details to make your descriptions more colorful.
In order to effectively describe a winter day to your audience, your description must do the following:
Present a clear, detailed impression of the events occurring on such a day.
Create the mood or atmosphere someone might experience on a winter day, thereby allowing your audience to conceive a picture in their minds.
Be organised to ensure that readers are not confused by the time sequence of events.
Please bear in mind, when creating a descriptive piece that you must be mindful of the context. This prevents your descriptive essay from becoming somewhat like a story. Also, there is a difference in telling what occurs on a snowy day and showing what occurs on a snowy day. A snowy day is very cold, is an example of telling. The frigid wind sneezed in the boy's face causing frosty snowflakes to lightly brush against the boy's cheek, however, illustrates a snow day and creates the mood for the description.