In the United States, winter generally runs from December to February. In most places, like Maine or Wisconsin, you can still catch decent snow suitable for snowmobiling until the end of March.
However, it is unlikely that you will find a spot in America with enough fresh pow to go snowmobiling in summer. To avoid snowmobiling on grass or water like slush here in the US, you will want to check out our list of 6 places you can go snowmobiling in the summer from abroad!