Here is a chart I found showing when snowmaking is possible, based on temperature and humidity:

https://www.snowathome.com/pdf/wet_bulb_chart_fahrenheit.pdf

I find it odd that 7springs is NOT making snow right now and it is 25 degrees there.   They didnt learn the last cold snap we had and opted not to make a single flake as they knew it was going to warm up.  At the very least they could have had a small base to blow ontop of today.

With the warm weather coming next week and snowmaking temps probably not returning for 10 days after Sunday, I doubt 7Springs will open this year at all!

Wintergreen will be making every effort to open this Sunday, even though they are fully aware that both terrain and the number of days the snow will last will be limited. See the Dec 18 entry in their blog:

http://wintergreenresort.com/Blog/

I really appreciate the level of detail they provide.