It seemed as though my luck with avoiding poor air quality for outdoor endeavors the last couple of months had finally run out.

I arrived at the Green Lakes Trailhead west of Bend on Tuesday morning, and I could smell the smoke from nearby wildfires.

“The smoke just arrived,” noted the Deschutes National Forest Service ranger at the trailhead as he checked my $1 Central Cascades Wilderness permit purchased two days in advance on recreation.gov. “It was bright, blue sky just 20 minutes ago.”

I fretted a bit about my bad timing, but then set out on one of the most popular hikes in the Three Sisters Wilderness.

Early fall is the perfect time for a trek to Green Lakes, as crowds have dwindled, permits are easier to acquire and — typically — the air quality is better than in mid-to-late summer.

The 9.2-mile roundtrip outing leads hikers and runners into the Green Lakes Basin, where South Sister and Broken Top loom over sparkling-emerald waters in a pristine nook of the Central Oregon Cascades. Along the way, several waterfalls surge on crystal-clear Fall Creek, which the trail follows through the wilderness.

Advance permits are required through Oct. 15, and after that, snow could become an issue, as the trail tops out at 6,565 feet in elevation.

On Tuesday, I awoke to clear skies in Bend, but after the 35-minute drive west of Bend along Cascade Lakes Highway to the Green Lakes Trailhead, conditions had changed.

The Green Lakes Trail has an elevation gain of 1,150 feet over 4.6 miles, so much of it is a gradual ascent, which is perfect for trail running. My plan was to run the flatter sections and walk the steeper portions, but considering the poor air quality, I decided to start out just hiking.

Yet after about a mile or so, the smoke had cleared, the mountain air was fresh, and I began to run on some portions of the trail.

Many trails in Central Oregon lead hikers through deep forest before the payoff of dramatic mountain views at the end. But on the Green Lakes Trail, hikers are treated to incredible scenery throughout nearly the entire path.

After the first half-mile, 30-foot Fall Creek Falls surges through the deep forest. Then, for the next 1.5 miles, a series of smaller waterfalls cascade along the creek.

Eventually I arrived at a junction to Moraine Lake, and the trail flattened out into an open meadow area. I crossed two footbridges, then began to climb again, switching from running to walking on the steep switchbacks.

Once I crested the next ridge, I took in the spectacular views of the shimmering Green Lakes with South Sister towering to the northwest and Broken Top jutting into the sky to the east. The air remained clear, making for stunning vistas of the peaks against the blue sky.

I continued along a trail that led to the south shore of the main Green Lake. The trail continues along the east shore of the lake to Green Lakes Pass at 7,035 feet, for even more breathtaking alpine views. Hikers can also complete a loop of Green Lakes, Broken Top and Soda Creek trails for a 13-mile trek.

After 20 minutes or so of resting and dipping my feet into the lake, I decided to head back. I was able to run almost the entire descent, encountering only a few other hikers along the way.

By the time I arrived back at the Green Lakes Trailhead, I had run/hiked 9.2 miles in about 2 hours, 30 minutes, with about 1,200 feet of elevation gain.

The clean air, smaller crowds and mountain scenery make Green Lakes an ideal option for hiking or trail-running in the early fall.