If you manage snow + ice, you know how difficult - or impossible - forecasting snow and ice revenue can be. And embrace it! It is impossible. If you did know exactly how much it would snow, you'd be making millions not running a landscape company.
So what do you do?
Forecast based on 3 to 5 year averages. Use 3-5 year revenue and/or snowfall averages to help you forecast your revenue for a 'typical' year. You're likely going to be wrong in every single year (we all are!) but the idea is that over a period of a few years, your average will be accurate.
There will be years where you sell more than you expected, and there will be years where you spend more than expected, but if your averages are accurate, you'll average out over time to a nice and profitable budget.