We did this trail on a sunny afternoon, August 4th. It is off McKenzie Highway 242, very close to the Dee Wright Observatory. This highway is subject to seasonal closures and is usually only open from mid-June to early November depending on weather. Due to wildfire damage in that area and construction delays, Google offers the way via Sisters as the fastest and it worked well for us. If you are up to the challenge and willing to fit two trails in one weekend, it is a great opportunity to add the Black Crater trail, which is a stone throw away.  You need the recreation permit for the Belknap Crater trail, which you can buy at recreation.gov (search for Central Cascades Wilderness Permit – Day Use and select Mt. Washington – PCT McKenzie Pass Trailhead, it is only $1 and was pretty easy to book). The trailhead parking is limited and the closest bathrooms are at the Dee Wright Observatory parking lot, 0.5 mile away. It was not crowded at all – only one other car was parked at the parking lot and we met only 5 people on the trail, all PCT hikers. This trail follows the PCT trail for the most part until the fork where you should turn left to climb the crater itself. The PCT part of the trail is going through extensive lava field with mild elevation gain but very rocky trail conditions. Good traction hiking shoes are a must. We lost the tip of one hiking pole due to a rough trail surface.  On the way to Belknap Crater, very close to the fork to turn off the PCT, there will be another sign giving you a choice to turn right to see Little Belknap Crater. It is worth a stop, but I would recommend to do it on the way back. The main elevation gain of the Belknap Crater trail is on the last part of the trail, once you turn left at the fork. You would see the Belknap Crater right in front of you and it looks very steep.  There are a couple of visible trails, but I would recommend taking the trail on the right because it is better marked and allows for a gentler ascent. The trail condition on the Belknap Crater itself is very sandy. Loose sand makes you think that with each step forward, you are taking a half step back, but don’t give up, it is a very doable ascent. Look back from time to time during the ascent, views are amazing on a clear day and give you a boost to continue your way up!  Once at the top, you can climb closer to the crater itself and have 360-degree views of the area.  You can see Mt Washington, Three Finger Jack, Mt Jefferson, Sisters, and Black Crater from the summit. Be careful while at the summit, it is very windy. All Trails app suggests taking another trail down, which starts next to the crater at the top, suggesting the descent from the left side.  Just a warning, it is not very well marked at all, and up until the middle of the slope, I kept questioning if it is the right trail and if we made the right decision to go that way. It is all loose sand, so you will find yourself almost sliding along the trail all the way down – you have to be very careful, and take your time. On the bright side, this trail is much faster, and it took us much less time to descend. The return was very easy and we stopped by Little Belknap Crater to enjoy views from another perspective. It is a short hike, maybe a mile or so back and forth, and you will have a 360-degree view of the lava field. There are also two caves formed by lava tube collapse, which are very cool to look in before climbing to the Little Belknap Crater summit. Overall, very cool trail, highly recommend hiking it at least once. Hiking through a lava field definitely adds uniqueness to this hiking experience.