SHMBO & myself have toured in some warmer climates, even the UK can get warm, occasionally, and our opinion is, while you are riding most of the time you are comfortable enough, when you stop is the problem!
Fifteen/twenty minutes for a coffee/water/photo stop we can cope with but if we decide we want a 'walk around' for a longer period in hot weather we have shorts 'T' shirts & lighter shoes in the top of a pannier ready to wear. We are more than happy to find a corner of a car park or similar to change into.
The 'biking gear' is chained to the bike. We use long bicycle style chains threaded through the arms & legs of the bike gear onto the bike.
We wouldn't do that in a town or city but then we wouldn't be in those places anyway!
In the evenings we find somewhere to stay close to a bar/restaurant, park & leave the bike, change into our 'evening attire' and walk.