Started our hike around ~10AM. The closest parking lot was full, but the lot across the street had openings. 

This is one of those hikes that requires very low effort but provides a very high reward! A gradual climb that rewards you with a stunning view -- Lake Diablo was turquoise as ever! The rocks at the lookout provide a great place to stop and eat lunch. 

This hike also provides great views of Colonial Peak. Wear sunscreen! Parts of this hike provide no shade/coverage. 

I’m sharing this as an overnight since we stayed at Colonial Creek South campground. We took our 3 kids on a trial run of backpacking and stayed in one of the walk in campsites. While not far from the car, about .15 of a mile, it’s uphill to get to it. We had everything we needed in our backpacks besides our tent, a few chairs and little cooler. We started with Thunder Knob on Saturday. Trail was a little busy but not as busy as I thought it would be for a sunny Saturday. Trail is dusty, has roots and rocks, but is done nicely that it doesn’t feel like you are always going up. Views at the top are so amazing! My 3 year old made it almost to the top. Next we did Thunder Woods Nature Trail. When they say steep on the sign, they mean it. The loop is just under a mile and off of thunder creek, so maybe 1.25 total. The trail I don’t think is used often because it is overgrown in places. You do cross a boulder field with some lose rock. But it was pretty in the mossy undergrowth. Has markers 1-16, which is kind of nice and it’s a 1 way going counter clockwise. Today before we left camp, we went out on Thunder Creek to the junction with 4th of July pass. The trail is also a little dusty but also has a few muddy spots. Roots and rocks but has minimal elevation gain. A few overgrown areas with ferns and devils club. If you have balance problems, probably not the best trail or maybe just take it slow. Some wildflowers blooming here and there. There is a pit toilet at Thunder Camp, so you can always stop there to use the bathrooms. And they have ranger talks in the amphitheater at 4 pm. So, if you are there around that time, Ranger Christi was doing a talk on bears.

Trail was in good condition - lots of folks on the trail as it was midday Saturday and the campsite was mostly full. Since it had been dry there was a bit of dust on the trail - the view up to the different peaks and towards the Diablo Lake dam was spectacular!

Camped at Diablo and wanted an easy hike we could walk to - Thunder Knob was great!  Trail is in great shape, easy to follow, nice views from the top...no complaints!  Bridge across the river had just gone in and I'm thankful it was there, the bridge is a little shaky so I would definitely recommend following the "one person at a time" signage.  

I’m a newbie at hiking and this trail was easy to follow. Was slightly out of breath on the steeper areas, but made it up with hardly any breaks (except for the views & photo ops of course)
That said, the view of Diablo Lake & surrounding mountains is just breathtaking at the top! The color of the lake looks way saturated up there, and it’s no wonder the lake is so highly raved in WA.