Typically warm spring conditions with the occasional snow storm. April is something like the 4th snowiest month. Last April was huge, we got around 15 ft of snow that month. Other years it's been all sunshine. As long as you don't get a cold front that rolls through with no moisture you should be alright. Otherwise you might as well be riding on the east coast during those days.
Anywhere between -10 and 50 degrees, sunny days with chances of clouds and blizzards. Anything from frozen pow under pow to pure ice. It really depends on the day. For the most part if it isn't snowing you'll show up to about 1-2 hours of ice on the groomers, then nice soft snow for the remainder of the day. If it snows it snows, and enjoy.