Weatherproof enclosures IP65 or Nema 3R, with specific holes, 150x150mm?
For the enclosure, Bud Industries makes a line of NEMA rated waterproof plastic enclosures. They vary in price from $10 to $50 from distributors like Digikey based on size and rating.

An example box that may fit your dimension requirements is the NBB-10260 (Digikey). It even comes with a clear lid for reading LCD displays if you need to.


An option for getting cables out of a box that I have used in the past is a Cable Gland.




You simply drill the correct size hole in your enclosure and tighten the cable gland around your cable.  If you adhere to the datasheet dimensions, it can be waterproof and dustproof.