Yeah, the thing about CT is that the rules are scattered all about. Later rule sets (especially MT) gathered everything up into the core rule book.
But, remember, back with CT, rules were written as needed. There are some zero G rules in the Traveller Book. But, when Beltstrike came out, extended rules came with them (a few more modifiers, really).
Same thing goes for what you're asking. Yes there are official rules. Some of the posts above will point you in the right direction.
Whenever I have a question like that, I just start thinking...which adventures address temperture and environment?
You'll find rules under equipment (like the environment suit listed in the Atmosphere special supplement). There may be something in JTAS about it. DGP's Grand Survey (or is it Grand Census? I get them confused) covers Vacc Suits better than any other listing in Classic Traveller.
Etc.
Stuff is around...you just have to look.
But, also remember that modern games have conditioned rpgers to not think for themselves. D20's "a rule for everything" has made people want to look up rules for every little thing.
Classic Traveller comes from a different mindset. It's not about "looking up rules". The CT rule set is more about giving you a framework on which to base your decisions.
So, if you need some rules about the environment, just make them up. Make up a quick rule about conditions on the planet you're going to explore. Use the examples in under the equipment and adventures to guide you.
The more "modern" way to do things...
"Hey Ref! I want to buy a laser pointer for my autopistol What kind of bonus am I looking at?"
"I dunno. I've got to dig through all this stuff and see if I can find a rule that covers that....I think I saw something in TTA 1..."
The Classic Traveller way to do things...
"Hey Ref! I want to buy a laser pointer for my autopistol What kind of bonus am I looking at?"
The Ref thinks for a second or so, then says...
"You get a +1 attack DM Short and Medium Range. Make it +2 DM at Close. No bonus at any range category at Long range or farther."
Boom. Done. Rule in place.