Its directly dependent on the location altitude. In early May after a normal winter, anywhere over 10,000 ft elevation may still be under snow.
I get to my summer home in Co around late April - early May each year and at lower locations I'll be out in T-shirt and shorts, but many of my favorite hiking, ATV & Jeep trails up at 10,000 ft will still be closed for snow. In this area (Rio Grande National Forest) the US Forest Service has locked winter gates across most of their high country access roads that they don't unlock until mid May most years. The main public hiways will be open, even over the high passes. Its the secondary & back country roads that are not a priority until most of the snow melts. Trail Ridge Rd, Cottonwood Pass Rd, Independence Pass Rd, Pikes Peak summit road, Mt Evans summit road and similar ones are frequently not open until June. The goal is to have them open by the Memorial Day holiday, but that's not always met.
Even later in summer, it can be 90 degrees in Denver while in the 30's on top Mt Evans (the highest paved road in the country). I've been snowed on in July & Aug while hiking up over 12,000 ft. It doesn't last long and the sun comes back in a few hours, but you need to be prepared in the high country.
Likes to tow wrote:
Planing a trip for next year and just wonder how much of Colorado is usable and enjoyable in the first half of May? I would think some mountain passes would still be closed but how much of Rocky Mt National Park could we see? How about the Scenic Highway of Legends, Maroon Bells and other top attractions??