If you can, ask someone already there. Depending on the exact type of work, they may have very specific recommendations, and they’ll have a better idea of what the climate is like than we will.

In general, you’ll want to be able to layer clothing. Start with the base layer, whose job is to be wicking away sweat.

Mid layers are for insulation, and it would be prudent to get one light sweater and one heavier sweater, maybe a third or whatever. The idea being you can increase your mid layers to stay warm but not too warm as necessary. Same for pants. Around here, I usually go for a tight base layer, a loser waffle-weave longjohns and shell blouses into boots.

Patagonia makes some good, hard wearing stuff as a general brand to check out, but there far from the only one.

Hats and gloves are important, too and for gloves I’d consider getting mittens at least as one option and maybe lighter fingerless gloves to wear inside. (Or lighter gloves. Especially if it’s possible you’ll need manual dexterity)