1. First, open the image you want to add snow.
2. Make new layer [on the top]and fill it with Black #000000
3. Then, Press Filter > Noise > Add Noise and use the following settings.
Now you have Black background with small white dots.
4. Then change the layer mode to "Screen"
5. Now press filter > Blur > Gaussian Blur & use following settings
Radius: 1.5 pixels
6. Then select, Image > Adjustment > Levels [Ctrl + L] & use following settings
Input levels : 90, 0.5, 120
Output levels : 0, 255
Now you've done!! :)
Some recent Snow and Winter Illustrations from My portfolio