We went up yesterday (Saturday,7/9) with a group of 8. Had great weather. We started at Marble Mtn Sno-Park (summer route still closed and probably will be for two weeks if I saw the road properly from the top). Plan on 6 miles one way and over 5,500' gain (rough numbers). Hiked in 2 miles and found a flat spot on dry ground to spend Friday night. Was about 40 degrees over night. There was spotty snow where the sun doesn't hit it all day, but nothing too bad.
You can climb much of the way up in the rocks but you cannot avoid the snow above about 6,000'. Many will argue you can make better time in the snow if you have crampons. 7 in my group had crampons and I didn't because of a mechanical issue. I would have put mine on if I could have. I didn't see many with crampons. The snow is melting fast.
Because 100 people are going up every day, some good areas with snow foot holds if you don't have crampons and are in the snow. So it becomes personal preference.
Did see a Forest Ranger up at the top. Be sure to have your permit.
I would strongly recommend an ice ax. There are a few steep areas and you need the ability to self arrest. I'd say 75% had them yesterday.
No need for snow shoes.
Bring sunscreen. Easy to burn even with a brimmed hat. Sunglasses to protect your eyes. 2-3 qts of water too. I hiked in a light long sleeve shirt and shorts with gaiters most of the way. But always prepare for bad weather just in case. Was probably 60 yesterday I guess with a light wind.
I was surprised more people did not go 1/8 mile to the west and get a good view of Spirit Lake and the crater. All that way up and you are missing some of the best sites. With that extra 1/8 mile, you can get very close to the rim edge, as the snow has already started to break away. It is flat, a little down and then a little up. Not too bad of an 1/8th and highly recommended.
Cornices at rim are very bad and most are getting too close in my humble opinion.
Another 1/8 of a mile will take you to the true summit. Very few tracks over here. Again, a little surprising. This is very icy with poor ice. Crampons strongly recommended and you have to have an ice axe. A bad step and it's a long way down in the wrong direction.
I echo the comments about plastic bags and snowpants for glissading down. That, and an ice ax to slow yourself down The best chute was right at the top - very smooth and straight. But you can get down very far by glissading.
I hope this helps. Have a great trip.