U.S. F-22 fighters, stationed in Guam, have developed electrical problems because of the very wet (100 inches, or 2.5 meters or rain a year) conditions in that part of the world. The high humidity meant that air intakes on the fighter, which help cool off electronic components, let in so much moisture that some electronics got wet and shorted out.
Such problems are common when a new aircraft operates in a new environment. This experience goes back to World War II. A more recent example was when joint exercises were first held in Egypt during the 1980s. There, U.S. aircraft and armored vehicles got their first workout in the Egyptian desert. Turned out the sand there was different than what was found in American deserts, and the standard air filters were more quickly overwhelmed. A similar problem occurred when large U.S. air and ground forces went to Saudi Arabia in 1990.
The sand problem and its impact on engines was known from World War II, and the engineers thought they had it taken care of in the decades after 1945. But it just goes to show you that you can't test enough for these things. This, despite the fact that new aircraft and ground vehicles go through extensive testing in deserts, rain forests and very cold environments. Moreover, you might not see problems develop until many vehicles have operated in new conditions for weeks or months.
These problems can be fixed rather quickly, although often with higher costs and more work on the part of the crews and maintenance personnel. In the case of the F-22 problem, temporary fixes were made, and some components are being redesigned so that they handle the high humidity better.