I second Joynz’s suggestion of Injinji socks.
Apologies, I rambled a bit, the TLDR version is, all of course IMHO:
Injinji socks are very good, worth checking them out.
Merino & coolmax both perform well in hot conditions, alone or as liners - merino in pretty well all conditions.
For your purposes: For calf length socks perhaps try a liner weight in coolmax &/or merino along with perhaps a light/mid weight merino pair.
For short socks try no shows in both coolmax & merino.
The above takes up little space and weight but gives some variety with the benefit of a low risk test to find what style and material you like best. Both will serve you well though.
My longer ramble:
Both their coolmax and/or merino liner socks should work well for you and can be used alone or combined with a second, outer, sock. Injini also have both low and no-show style socks, the no-show are my go to for hot weather with lightweight shoes. As I recall, for the no-show style of their socks, there is greater variety of weights & cushioning in the coolmax versions. I have quite a selection and to be honest I don’t notice that much difference between them.
Regarding material: I use both and again, personally, in hot conditions don’t notice a huge difference between them. Merino tends to smell less, or last longer before it smells. Coolmax may wick a little more moisture. An advantage of merino though is that, when temps cool down, more heat is retained even when it’s wet.
I’m a fan of Injinji’s toe-socks (though I also use their, and others, regular style socks). The liner socks function perfectly as intended, liners with whatever weight sock suits on top, but also on their own as lightweight socks. - As an aside, don’t automatically assume a second layer will be too hot, the liner can have a wicking effect which helps cooling. It’s sometimes about finding the compromise; for example a little warmer but reduced chance of blisters vs a bit cooler with increased chance of blisters. The wicking effect of a liner can also be quite effective, even with heavier outer, at maintaining a regular temperature.
I am a real fan of merino in general. It features throughout my wardrobe from socks & underwear to various clothing layers and has worked well in any environment I’ve used it, hot & cold. Of course there are materials that will beat it in a given condition, though not always by a huge amount, but few, if any, can match it across a range of conditions. It’s one of natures wonder materials and, in my experience, it’s tough to go wrong with it.
In hot conditions I use the low no show socks and because they’re so small it’s no hassle to carry spare, either to double up or to have a dry change. I also take a pair of calf length liner socks so I can cover ankles if needed, again they're light enough not to think about. Feet are worth taking care of so, in addition to the socks I’m wearing, I aim always to have a spare pair for the day and a dry pair for evening.
Enjoy your trip and the experience.
www.enformasocks.eu
www.smartwool.co.nz
