I walk/hike almost every day in temps that can range from below 0°F to 100°F or more. You ask about the 30° to 50°F range, so I’ll assume you’re looking for help selecting clothes for when you’re on the move, since requirements at rest are, of course, very different. The clothing system described below is based upon many thousands of trail miles hiked over a lot of years. It also reflects my objective of keeping it as simple/light as possible and of avoiding overheating, especially when it’s cold. I should note that when I stop/rest in temps below 50°F or so, I usually wear a puffy jacket of some sort (in addition to the clothes noted below) for additional warmth.
When I’m on the move in temps above 60°F, I usually wear just a Capilene (midweight or lightweight) long-sleeve top and cordura nylon trail pants. From 60°F down to 40°F, I add a light (5.5 oz) Patagonia Helium windshirt. When the temp enters the upper 30’s, I add a short-sleeve 100-weight fleece jacket (North Face Salathe with the sleeves cut off at the elbow) under the windshirt. I also usually add wp/b windpants over the nylon trail pants on the bottom. Further, I usually switch from the Helium windshirt to one with a hood. My favorite is a Feathered Friends Epic Jackorak (a little heavy, but worth the weight in cold weather).
Though you didn’t ask, when the temps are from 30° down to 20°F, I add the fleece jacket pull-on sleeves. When the temps enter the teens, I add a second 100-weight long-sleeve fleece jacket and lightweight Capilene long johns under the trail pants (3 layers total on the bottom). When the temp drops into the single digits or below, I’ll probably replace the two 100 weight fleece jackets with a lightweight puffy jacket such as the Patagonia Fireball (no longer made).
When it’s cold, I also usually hike with Capilene liner gloves, ear muffs, and a 100 weight fleece face scarf. I rarely use a hat on the move, since I tend to overheat too quickly. If it’s raining or snowing, I’ll use an umbrella if the wind is not too bad, otherwise I’ll switch (begrudgingly) from a windshirt to a Marmot Precip jacket. I’d love to ditch the Precip, however (not very breathable when exerting), and am looking forward to trying an eVent hard shell. In cold/windy rain, I also use GoreTex shell mittens over the Capeline glove liners as well as GoreTex oversocks inside my trial running shoes. When hiking in moderate snow (up to a foot or so), I often use instep crampons for traction. Summer or winter, I wear New Balance trail running shoes and 3-ply ragg wool socks (maybe two pair if it’s really cold).
Hope this helps…