I am currently living in South Africa (where Lowa products are not available) but I was back in the USA last month and purchased a pair of Lowa Zephyr Desert Mid for some light hiking on our dry warm climate. They are non GTX and are fantastic boots.
I am in the process of purchasing a pair of hiking boots as I am going on a two month "walkabout". I have picked out a pair of Lowa Renegade's - one comes in Gore-Tex the other in a non GTX version. I like the look of the GTX pair, but think it might be a little on the warm side for some warm/temperate weather hiking. I have been told by some that GTX is way too hot for serious warm weather hiking as one's feet will really perspire heavily as higher temps will slow the transfer rate down of moisture from inside the GTX boot to outside.
I will encounter some wet conditions on my hike, but not continuous rain, river crossings or cold.
Has anyone used GTX boots in warm weather?