Ok this is one of those achievements that you will capture over time if you have the Snowfall DLC for City Skylines so I was reluctant to post a solution. However, if you would like to make it easier to obtain, here are a few tips.
First, you need to pick a winter map to have snow. Unfortunately, at the time of this post, it stays winter the entire time, but there are fun unique winter themed parks to go along with it (for instance, a sledding hill or an ice sculpture park).
Second, in order to collect snow you need Snowplows (think Homer Simpson as Mr. Plow). You get snow plows by putting down Snow Dumps.
Third, the more snow dumps you have, the more snow plows you have so if you want to speed up the achievement, put down more snow dumps and have more plows.
Finally, if you have more roads to plow then your snow plows will collect more snow as they have more surface area to plow. So a bigger city will get this achievement quicker or at least a city that has more roads to plow will get it quicker.
Hopefully this helps you. I unlocked this when I had around 25,000 citizens so it took a little time but I was also not speeding up time to get it.