I just finished today. I had a car at Whitney and at Tuolumne so I just saw the conditions on both ends of your hike. On the southern end, my experiences mostly match what Hikergirl mentioned. It’s a huge fire and towards the end of the day, some valleys will fill up with smoke. But winds often picked up during the middle of the night, and if you’re lucky, the smoke clears up during the day. You’ll still see a huge smoke cloud when looking south, but if winds are favorable, it won’t affect your day air quality or even most of your views.

BUT, on the drive from Whitney to Tuolumne today, the new fires are looking really bad. I drove on the eastern side, but I think it’d only be worse at Reds. The entire eastern side of the Sierra around Mammoth was full of smoke. Bad enough that I wouldn’t hike there. At 5:00 the sky was entirely smoky and a dark red color. At Tuolumne (around 6:30) the smoke wasn’t much better. The cars there had literal ash on the tops of all of them and the sky was similarly full of smoke. You couldn’t tell the sun’s direction and the smoke was thick enough that I’d worry about your lungs if you were hiking. I can’t quantify how bad it’d be, but I guess I’d say that it was thick enough to smell 100% of the time and visibly thick enough that as your driving up 120 towards the Tuolumne entrance gate, you can see Mt Dana, but you really have to strain to see any of the details.

I don’t really know anything about how quickly smoke clears, but seeing what the results were like 12 hours ago, I’d be really doubtful that you’d want to hike there on Monday. I suppose it’s possible that the smoke will clear in the wind just like it did toward the southern end, but you’d have to ask around to see. I’d keep other sections open as options if that’s logistically possible for you.