This is a quite big update of my mod who replace rain by snowfalls in gta IV.
Now the snow and atmosphere is even more realistic, with correction of some details quite ugly (colour of the ground under snow, sky colour etc...)
And if you use the Snow Mod v2 (by Jumbo0), the ugly "grass" effect on snow could be disabled.

Here is the list of the changes :
-snow is more intense and heavy.
-snowflakes are biggest under snowfalls.
-snowflakes are less big and dense with wind, under blizzard.
-the colour of the ground in now almost exactly like the colour of the sky (for day and night), like during real snow weather.
-there is less luminosity in the night when it's snowing.
-the differences between all kind of snow weather are now better.
-you are now free to increase or decrease luminosity and / or contrast, it's "always" realistic, unless you put all those settings to maximum or minimum.

Have fun