New to Colorado
Simple formula: 55 degrees, completely calm air, sunshine. That is really all you need from mother nature. Take along some insulation from the ground (yoga mat which adds a waterproof barrier, or a thermarest) and you can enjoy a beautiful day, even in February. You just need the location. You can even go there wearing snowshoes. Find a perfect spot, stomp the snow down to make a good, flat platform and set up shop somewhere secluded.
Just because the days are getting cooler does not mean that the opportunities are gone. It means they are not as easy...although, with snow cover you can get to places off trail that you could not go to before. As long as the air is still, the air is fairly warm (45-55 degrees) and you have a clear day near the noon hour, you have a good day. Just be careful not to get burned due to the added sun exposure caused by the sun reflecting off the snow, which results in you getting the sun from multiple angles and increasing your exposure.