From time to time people ask me about suitable riding gear for hot and humid conditions as we have them here in the Philippines. Here's what I can suggest after three years and about 30,000km of riding here.
Don't be fooled by the fact that "everybody" appears to be riding in shorts, t-shirts, slippers and probably even without helmet.
At least here in the Philippines, the majority of locals ride slowly, very slowly. If you are used to ride in the west, chances are you will ride faster. Second, here in the Philippines there are laws that, besides making helmets mandatory, even regulate pant length (long) and footwear (closed). As usual, the level of enforcement varies, but it may happen from time to time.
Around town I use a relatively lightweight full face helmet (LS2 Pioneer, to be exact). I removed the visor for better ventilation and use sun glasses instead. I wear sneakers or lightweight hiking boots and often light gloves (MX gloves like the Alpinestars Techstar work great). Occasionally I ride in shorts and T-shirt, but feel better with long pants and my riding jacket, and if it's just for sun protection.
A bit more info about that jacket. I've been looking for quite a while and then stumbled across the Assero brand which is based in Thailand and Indonesia. They fabricate gear for the South East Asian Market and naturally pay big attention to ventilation. I got the Air Blast Mesh & Cordura Jacket and I really love it. It is equipped with elbow, shoulder, chest and back protectors and still does not make me sweat too much while riding. Plus, after several years of nearly daily use it still looks like new. It already saved my shoulder once when I hit a mini bus that decided to do an unannounced U-turn in front of me.
I don't race but I don't go slow either, so I decided to invest in proper offroad gear early on. I wear Alpinestars Tech7 Enduro boots, wich I like for their contoured sole that gives grip in case I have to walk a bit or wrangle the bike in rough terrain. I use Klim vented socks in these. It obviously gets a bit hot in those boots but wile riding I don't notice. The socks do a great job of keeping things comfortable.
For protection I wear Fox Titan knee and elbow protectors. Alpinestars Bionic Freeride shorts add further protection for hips, thighs and tailbone. Hip protection is often overlooked, but in a crash chances are one of your hips will hit the ground first. Nice to have some padding there then. I also own an Alpinestars Bionic Chest protector but I admit I rarely use it. It is well ventilated but adds quite some bulk and as long as I don't ride faster and/or single track in a forest I figure I can do without it.
Lightweight Fox Racing in-the-boot pants and a Klim Mojave Jersey complete the outfit. The Mojave Jersey is really well ventilated and I usually wear some base layer under it - even if you start riding in 30 degrees on sea level, it may get a bit fresh up there at altitudes > 1000m…
I use the same gloves off road that I use around town. Recently I got myself a dedicated offroad helmet though - the LS2 Subverter. It's very lightweight and has superb ventilation. Highly recommended.
For road riding I got Forma Adventure (low) boots which are comfortable enough to also walk around a bit. They don't look too technical as well (compared to the Tech7 at least…). On longer trips I wear dedicated motorcycle pants (the Scorpion XDR Yuma Motorcycle Adventure Touring Pant, to be exact) wich I find to be more practical and comfortable than normal long pants. Not to mention the much better abrasion resistance and added protection through integrated pads for knees and hips. They also dry very quickly should I encounter some rain. The Assero riding jacket mentioned above protects me from the sun and (hopefully) anything else I might encounter.
My helmet for touring is a Bell MX-9 Adventure. Works with Googles but most of the time I'm fine with the auto-tinting visor. I have Fox Racing Bomber gloves for road use. They are slightly heavier than MX gloves and have solid plastic knuckle protection.
Forget GoreTex etc. All these "waterproof" membranes will not help you in a proper rain storm, but will make you sweat the rest of the time because they get in the way of proper ventilation.
I bring a dedicated rain jacket and, in rainy season, waterproof pants on longer trips. In general, due to the usually hot weather, rain isn't that much of a problem. In rainy season with a typhoon coming, it's best to stay at home anyway or at least not go on an extended trip. Other than that, rain often goes as quickly as it came and proper riding gear will be dry again in no time.
Other bits and pieces
On longer trips I use Alpine MotoSafe ear plugs against the wind noise. I arrived at these after some experimentation and I really like them. A Klim Aggressor Cool neck sock protects my neck from wind, heat and, to a degree, cold (should that ever be necessary). When wet, it provides a nice cooling effect.