Sleeping bag Rating - Gannett Peak. Last week in June

We are in the process of planning a trip to Gannett Peak for the last week in June. I am wondering which sleeping bag to bring since I have seen different average temps for the range at this time. If it would be sufficient I would bring my 32 Ultralamina for the weight and packable size. Otherwise it is going to be the phantom 0 degree, which is the direction I am leaning now. We are planning to be up in the basin for a few days so comfort might be the trump.

Any input would be appreciated.

I dunno about bag temp ratings, but I'd plan on some snow above TL in late June. Based on Colorado late June outings, I'd guess overnight frost is unlikely below 12,000'.

At a quick glance, @ NOHRSC & SNOTEL data, the winter was relatively dry in the Winds, so it should be less snow bound than the last couple years. Mosquitos in the forest are likely to be intense, and there could be some stream crossing issues.

You might be interested in the NOHRSC snow cover map:
http://www.nohrsc.noaa.gov/interactive/html/map.html
Note that it has historical model data back to 2004, and you can zoom in to your area of interest. I believe its 1 sq km resolution (painted over a 100 meter or so digital elevation model (shaded terrain) map.

I was in that area that time of year two summers ago. I've got a 15 degree bag. I had that bag, a foam pad, bevy sack and big mosquito net (ESSENTIAL!!!) and I was quite comfortable.