It's nearly summer. Birds are migrating, flowers are blooming, and REI is kicking off its annual anniversary sale. It’s the outdoor retailer’s biggest sale of the year. This year’s REI sale starts May 15 and runs through Memorial Day, May 25. Many items are up to 30 percent off, but REI Co-op members save up to 20 percent on any full-price item and an extra 20 percent off any REI Outlet item. To get the discount, add the promo code ANNIV26 at checkout. We’ve highlighted the best deals on gear we’ve loved over our years of testing. There’s something for nearly all our favorite summer activities: tents, stoves, sleeping bags, and plenty of outdoor apparel. Be sure to look at our guides to outdoor gear, like the Best Tents , Best Sleeping Bags , Best Backpacking Sleeping Pads , Best Rain Jackets , Best Backpacking Water Filters , Best Merino Wool , and Best Binoculars .…