Do I need to weatherproof my outdoor conduit?
Short answer: Wet locations only require corrosion resistant materials. But I would use compression connectors outdoors anyway.
From the National Electrical Code

358.10 Uses Permitted.
(A) Exposed and Concealed. The use of EMT shall be permitted for both exposed and concealed work.
(B) Corrosion Protection. Ferrous or nonferrous EMT, el-bows, couplings, and fittings shall be permitted to be in-stalled in concrete, in direct contact with the earth, or in areas subject to severe corrosive influences where protected by cor-rosion protection and approved as suitable for the condition.
(C) Wet Locations. All supports, bolts, straps, screws, and so forth shall be of corrosion-resistant materials or protected against corrosion by corrosion-resistant materials.

Good luck!