Nitrile is the rubber everyone asks for, and for anything touching oil it is the right answer. Put the same nitrile washer outdoors in the sun and it is a different story.
Nitrile does not like ozone and sunlight. Over a season or two the exposed surface develops fine cracks, usually across the direction the rubber is being stretched. The washer still looks black and still looks like rubber. It just is not sealing any more.
Neoprene handles weather much better and has moderate oil resistance. EPDM handles weather best of all, but swells in oil.
So the honest question for any outdoor rubber part is what it touches and what it sees. Oil and shade, nitrile. Weather and no oil, EPDM. A bit of both, neoprene is usually the sensible middle.
If a rubber part on an outdoor panel is cracking after a monsoon or two, this is the first thing I would check.