It’s going to be 95 where I live today. This isn’t even a full-blown heat wave. I’ll be hiking later this afternoon.
Heat acclimatization is real. I think this is part of what’s getting lost in this discussion…and not just acclimatizing to temperature, but also to clothing. I can understand that sweating in full coverage clothes with a hood would feel disgusting if you don’t do it regularly. But for me to hike safely year round, it’s a fact of life that I came to accept long ago. If I visited the Sierra to hike once per summer maybe it would be different. But I live in those conditions all year.
Something to note: you will rarely if ever see construction workers, gardeners, or farm workers in short sleeves or shorts (let alone exposing their ears and necks) anywhere in Southern CA, even on the hottest days. There’s a reason for this.
If all the clothes feel “gross”, it’s better than the alternative.