Raingear is something that you carry in your backpack most of the time.
It seldom happend to us more than a few days of rain in a row. So maybe we were always fortunate.
As a matter of fact you carry your rain gear as long in your backpack as it isn't raining. This means it is most of the time useless and burdens your pack with an extra weight.
So all UL-hikers try to minimize their rain gear weight. And yes for sure you may leave your rain pants at home just to save some weight and hope that it will not rain that much. As Andrew Skurka puts it, this is "stupid light".
Others buy super ultralight waterproof and breathable rainpants and rainjackets. Their mayor drawbacks are their short term waterproofness. If you don't keep them clean and don't reimgregnate them after every cleaning they render useless because they won't be waterproof and breathable any more.
Even if you use them brand new, they are breathable as long as you stand there studiying your map. As soon as you start to hike you get wet and sweaty and as a result you will freeze on colder days.
