Whenever it rains...
I use this every time I see the sky darken, which in DC, is quite frequently.
This is the best rain jacket I have EVER had. The waterproofing is fantastic and I dont get that feeling of being wrapped in saran wrap that you get with a lot of wet gear. The breathability is great and you dont get the sauna effect, even when you are in a warm day downpour.
I pair these with Sierra Designs Hurricane pants, SD gaiters and my Mammut backpacking boots and I can hike endlessly in the rain without the worry of getting even slightly wet.
Don't be a fair weather outdoorsman, get some good wet gear and own all weather conditions.