Are butcher-block countertops appropriate for a very hot and humid climate?
In my opinion, wood is a very poor choice for kitchen counter tops. Any wood is dimensionally unstable to some extent, how much depends on several factors such as moisture content during installation and method of construction. It can be relatively stable or a complete disaster.

My main objection is wood is porous. Ideally, kitchen countertops should be impervious. Most materials have pores to some extent, but they should be as microscopic as possible. Wood pores are relatively gigantic. While oiling is helpful, wood will get stained from food and other products that come in contact with it. Some may say this gives it character, but to me, it just looks unsanitary.

Speaking of sanitary, despite the moniker 'butcher block', meat should never be processed on a wood surface. It is impractical to properly sanitize wood in the home. Chop all the fruits and vegetables you want on it, but only  cut meat on a dedicated impervious cutting board that can easily be sanitized.