At an elevation of 7,000 feet above sea level, the South Rim of Grand Canyon National Park has a near-perfect climate year-round. With four distinct seasons and all of them ideal for visiting, there is no best time to plan a Grand Canyon vacation at the South Rim. However, the most popular season is summertime, roughly May through September. But one shouldn't be discouraged from visiting any other month; the Canyon is spectacular in winter, dusted with snow, and the shoulder seasons of fall and spring are supreme in their vivid turning leaves and blooming wildflowers.
The climate and its effect on the Grand Canyon's ecosystem is fascinating, and there are excellent sources of information on it, like the National Park Service's page found here. But what interests most visitors, when it comes to talk of the weather, is knowing in advance what to expect so they can pack and dress accordingly.
With daytime temperatures ranging from 70°F to the mid-80°s and overnight lows in the mid-40°s to upper 50°s, your best bet is to pack layers. Layering your clothes will help you go all day, adding and removing layers with changing conditions. You'll go from fully layered up, standing on Yaki Point for a very chilly pre-dawn hour before sunrise, peeling down during a warm midday walk along the Rim Trail or partway down Bright Angel Trail, and piling back on for an afternoon Monsoon storm or rapidly declining temperature as the sun sets over Hopi Point.
Fill your suitcase or backpack with tanks and tees, long-sleeved tees, shorts, pants, long-sleeved button-down shirts and a mid-weight waterproof jacket. If you're hiking down to the Colorado River, be sure to wear socks and hiking boots that are broken-in and comfortable, and because you may want to wade in Bright Angel Creek near Phantom Ranch at the bottom of the Canyon, pack a day pack with a pair of water sandals among your other essentials. On the rim and down below, always wear sunscreen, a brimmed hat, and sunglasses if you wish.
With the snow comes a sense of peace and solitude at the South Rim. Certainly less congested than any other time of the year, visitors will find sparser crowds at viewpoints, attractions and visitor areas. The absence of crowds means there's better opportunities for lingering over a hot beverage on the Rim, and spending time during crisp, sunny days walking the Rim Trail and hanging out at overlooks, marveling at the way a dusting of snow defines each million-year-old textured layer of rock below. The key to enjoying your wintertime visit is to bundle up.
Pack and dress in layers. Thermal underwear, long-sleeved tees, flannel button-down shirts and sweaters, warm pants, a down vest and/or parka, gloves, hat and scarf, wool socks and boots are the layers that will take you through the short, cold days on the Rim. Like any other season, you'll want to be able to add and subtract layers as the frigid mornings warm to crisp and sunny afternoons. Because the days are often sunny and you're at a high elevation with thinner atmosphere, don't neglect the sunscreen. You don't want to be deceived by cool temps and come home with a wicked burn across your nose and cheeks.
In December through February, daytime highs hover around the low 40°s, while temperatures plummet to the teens and low 20°s overnight. Snow frequently falls at the South Rim, making for more careful but still possible hiking, especially along South Kaibab Trail, and slower driving conditions. If you encounter snowy roads, approach the South Rim via Williams on Highway 64; it's your best bet for timely snowplows and road salt.
The shoulder seasons at the South Rim of the Grand Canyon offer a glorious color story. The Kaibab Plateau surrounding the South and North Rims is ablaze with wildflowers from late March through May and with golden aspen in early October. The spring and fall are less crowded, but if your travel dates fall in March-April or October-November, you'll still be able to find the full array of Ranger Programs, free shuttle bus routes, and other peak-season programs.
Spring weather can be slightly unpredictable, with late-season snow and rain storms, or unseasonably warm temperatures. However, the typical highs in March and April range from 50–60° F. The overnight lows are freezing, from the mid-20°s to the low-30°s.
Likewise, autumnal weather can swing by the day or the hour. You may encounter rain or early snow, but it's just as likely you'll encounter warmer-than-usual temperatures. That said, it's wise to plan for the average weather for October and November, which is the low-50°s to the mid-60°s during the day and temperatures near freezing overnight.
Your suitcase may look at best like a hybrid between summer and winter, and at worst, like it has multiple personalities. But like the other seasons, layers are key. The layers you should choose in spring and fall are: tees, shorts, pants, light sweaters or flannel button-down shirts, a down vest, a mid-weight waterproof outer layer, a hat and scarf. Appropriate, comfortable socks and footwear are important for hikers and Rim Trail walkers, and you won't want to forget the sunscreen and sunglasses.
The North Rim sits at nearly 8,000 above sea level, and that, coupled with its short summer season from mid-May through mid-October, makes the North Rim a comfortably cool, pine-scented paradise.
Summertime visitors can expect low-60°s to high-70°s during the day, and mid-30°s to high 40°s at night. Understand that as you descend into the Inner Gorge, temperatures will climb; you'll notice up to a ~27° difference between the bottom and the Rim.
Pack your bag with layers you can add and subtract as the long summer days progress. Start with a cautious, pre-sunrise walk out to Bright Angel Point to wait for the sun to break over the Rim, and be sure to pack a flashlight and plenty of warm layers to stave off the chill, even in the peak summer months. To be able to stand outside for an hour in the freezing morning temperatures, wear thermal underwear or lined pants, a tank, long-sleeved tee, sweater and down vest. For daytime hiking, you'll want to shed layers down to a tank or short-sleeved tee, pants or shorts, and a long-sleeved shirt.
Grand Canyon West is warm. It just is. Year-round, this remote desert attraction on the West Rim of Grand Canyon experiences sunny conditions, with little vegetation to provide relief. For this reason, Grand Canyon West is a perfect destination during the late fall, winter and spring months, making it super appealing to visitors, virtually regardless of their travel dates.
Year-round, pack and dress for the West Rim like you would for Las Vegas or Phoenix. Shorts, tanks and tees, a light waterproof jacket if the forecast warrants it, hiking or walking shoes, a wide-brimmed hat, sunglasses and lots and lots of sunscreen.
Summer temperatures can soar well over 100°F, which can make waiting in lines for shuttles and the Skywalk somewhat uncomfortable. If you're headed for the West Rim from May through September, be prepared to experience hot, dry summer temperatures and wear tons of sunscreen and/or a wide brimmed hat and drink plenty of water. Average summer temperatures at the West Rim range from the mid-90°s to 102°. Most visitors won't experience the overnight lows at the West Rim, since it's open daily from 7:00 am &ndash 7:00 pm in the summer, but if you should be one of the few who stays overnight at the limited lodging near the Rim, expect overnight lows from 65° to 79°.
From December through February, expect extremely pleasant daytime conditions in the mid-60°s to low-70°s. You may want to throw a long-sleeved shirt in your bag along with the tanks and shorts enumerated above, but essentially, you'll be comfortable in a minimum of layers.
The shoulder seasons of spring and fall are perhaps the ideal time to visit Grand Canyon West, especially if you like daily temperatures in the mid-70°s to high-80°s. The spring and fall wardrobe is virtually the same as the summer packing list; you may pack more tees than tanks, and throw in a pair of pants in place of one pair of shorts, but other than that, dress in order to be comfortable standing still under direct sun.