One of our favorite hikes. Did it late evening this time to catch the sunset on this warm summer day. Only one other car there when we parked, just a woman and her dog whom we saw on the trail. No one else there. Trail is in good condition. They brought in more rocks to reinforce the path on the lower switchbacks. We were psyched to see Mt. Rainier from the top for our first time. Every other time, it's been behind clouds. Mosquitoes were aggressive and hungry, even at the top. We descended as darkness fell and used our head lamps for the lower half. Great hike!

The forest road up to the trailhead was quite dusty and bumpy with huge potholes. We were able to navigate it in a Subaru Outback, but I personally would not attempt it in a sedan. The trailhead is unmarked at the road (see attached photo), with a sign that only appears after hiking up the trail a bit.
We arrived around 2:30pm to only a few cars parked at the trailhead and had the trail mostly to ourselves. It was hot and dry with a slight breeze nearer to the summit. Lots of loose rocks on steeper parts of the trail, highly recommend trekking poles. Great views on a clear day!
The hike took about 2 hours total, with 1.5 hours up and 1/2 hour down. GPS indicated 2 miles up and only 1.5 miles down (go figure). We were moving at a slower pace due to the 85F heat.
Tons of mosquitoes that seemed to be kept at bay by bug spray, but I later found bites that came through my shirt where I missed spraying!

Gorgeous, quiet trail with amazing payoffs.

I had never hiked or heard of this trail despite decades in the area and continue to be amazed when I share it with friends that it's so little known!

Perhaps the slightly worse than average forest service road (at least for the area) scares people away but it was 90% doable in any vehicle with a lot of care which would add just a short walk. In any suv it was passable with ease.

The bugs at the Trailhead were expected and annoying, but it felt fine while walking.

The sign at the Trailhead was missing but it's the only one on the right as you head up at the designated spot on Google maps and based on mileage on the description so it wasn't hard to find.

Lots of rocks early on so I had to be a little careful with my ankles. The trail is mostly shaded, necessary on this 90 degree day!

After gaining the ridge, I didn't notice rainier for a while but the views were still getting really good. The elevation doesn't really taper as much as I expected.

Once right below the summit it can be a little tricky to find the right boot path - I certainly don't recommend trying anything with the steel cable, that looked dodgy.

I believe I went up the right most path and did have to pull on a branch or two to steady myself putting away my poles for the final bit and the best way down felt like sitting and scooting.

Once at the top, the views are nearly unparalleled for hikes of this distance and difficulty. Between complete views of Rainier, all the lovely Snoqualmie Pass peaks and the constantly flirting butterflies of various sizes, it was easy to pass an hour on top, helped by the fact that no one joined me during that time until I was just heading down.

Reapply sunscreen and especially bug spray before the top though as I thought I was OK in my shirt but ended up with no less than 50 bites as a reward for lots of lounging and lots of photography where I was trying to stay still and capture butterflies with the mountain in the background.

Make sure to find and sign the trail registry under a tree.

I was extra surprised as I heard the bugs more than I saw them and I don't think they were all mosquitos. Regardless, the bites healed and I'm left wanting to go back to Mount Catherine as soon as I can.

Will switch out some pictures as I process them.

This was my first time hiking Mount Catherine and it didn’t disappoint. Spectacular 360-degree views. 1,300 feet in 1.5 miles was a good workout.

Note that the trail sign is actually 100 yards up the rocky start of the trail, but the trailhead is not hard to find.

The road has unavoidable potholes. I think I had the only 2WD vehicle out there and my Sienna scraped bottom a few times. There are several areas where the road appears to be in the process of washing out and these areas have exposed rocks that aren’t tire friendly.

The trail was bug free until the very top. I recommend loading up on bug spray just before you start the almost scramble to get to the top. I was swarmed by mosquitoes and bees at the summit.

Saw a couple of reports from the same day already, so not much more to add. Some data points.
I arrived to TH around noon, there were 4 other cars there.
On the way up I passed 3 parties coming down. There was one party at the summit when I got there. I passed nobody coming up when I came back down, and back at the TH around 1:30 and there was only one other car there (assuming the party I met at the top, as I descended faster than them).
Bugs were pretty bad, I got a lot of bites.I did not have any bug spray unfortunately.
And because someone else mentioned it in their review, my Garmin had the round trip at 2.82 miles. So, not sure how someone got 4 miles.