April is the start of the dry season in Peru, Ed, so that's one thing to consider. Not as dry as May or June, but pretty dry. Still, it's also the transition month, and it might not transition fully to the dry" when you're there.
So, rain gear. Yes. Waterproof-breathable. Yes. But nothing too exotic or expensive or heavy. You need something for showers or that will suffice if you hit some extended rain. These days, the default position for those parameters is the Marmot Precip Jacket ($99; marmot.com), which uses a polyurethane coating to create a waterproof-breathable piece that fills the bill nicely as a when-you-really-need-it jacket. Is the Precip as breathable or durable or full-featured as a $380 piece from Marmot or Mountain Hardwear or Arc'teryx? Of course not. But it works fine. I also like REI's Ultralight Rain Jacket ($119; rei.com), which uses a waterproofing system basically the same as the Marmot but adds stretch in key areas for a little more comfort. And, if you want to spend a little more, Patagonia's Jetstream Jacket ($225; patagonia.com) offers a superb, trim fit and high-end construction in a very light jacket.
An intriguing alternative is the Cloudveil Inertia ($150 without hood, $160 with hood; cloudveil.com), a super-light soft shell that is more of a light rain jacket. That means it will keep you dry most of the day in light rain and part of the day in heavy rain. Plus, it breathes better than the pieces above, has more stretch, and dries out quickly if it does wet out. In other words, it's perfect for a day when you're hiking through intermittent showers or light rain, which sort of sums up what you might face. It's probably what I would take, to be honest.
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