South Kaibab Trail - Grand Canyon
The South Rim is open year-round (except for road closures during extreme winter weather, which is rare). The best time to hike the trail is spring or fall, but it also depends on what you are looking for:
March, April, May (spring): Spring weather can be unpredictable but usually temperatures are mild without a lot of rain. However, March is prone to late season snowstorms. Spring is great if you want to avoid the hot and uncomfortable summer heat. It’s also not heavily crowded. There are wildflowers blooming during this season. In some years it can be a gorgeous with lots of blooms.
June, July, August (summer): We do not recommend summer as an ideal visiting time: These are the most popular months with heavy crowds. Although the temperatures are more pleasant than the extreme inner Canyon heat it’s still very hot and midday temperatures can make hiking unbearable. Afternoon rain showers or thunderstorms are common in the summer. Especially from from July through mid-September. Always bring rain gear.
September, October, November (autumn): September after Labor Day is the perfect month for hiking the trail: Less crowds and very pleasant temperatures. However, keep in mind that until mid-September those summer thunderstorms can still occur. Fall weather is also the most unpredictable: Bring rain gear. October and November are still great, although temperatures drop in November: 27 - 52° F (-3 - 11° C)
December, January, February (winter): It’s colder with daily highs in the 40s. Extreme weather with snow storms and and icy trails is possible. However, in the winter you’ll almost find solitude with minimal crowds and reduced rates. It’s a great time if you don’t mind the cooler climate.
Avoiding the Crowds
Summer months bring the most crowds. If you visit in the summer start your hike very early in the morning to beat massive crowds as well as the heat. It can also get crowded in spring and fall during holidays and on weekends. Try to avoid weekends in general. Some great tips from the official NPS website to dodge the crowds: South Rim Crowding: South Rim - A Survival Guide
Please check the monthly weather with temperatures and precipation here: South Rim Monthly Averages. Remember to bring rain gear, regardless of the season.
We did this circular hike in one day, started very early in the morning. We parked the car at the Bright Angel Lodge and took an early shuttle express bus to the South Kaibab Trail head. It was 2 degress in the morning but usually temperature rises very soon. It took us 3 1/2 hours on the steep trail down to the Colorado River. We arrived before midday and had a long break to recover. It is important to drink plenty of water with electrolytes, which you usallly take for diarrhea. After midday it was almost 40 degrees and there isn't much shade.
The way back on the Bright Angel Trail is less steep but even more strenuous. In total it is an 26 km hike and an altitude difference of 1400 m. The trails are well maintained but you have to share with mules from time to time. You can't refill your water at South Kaibab Trail but several times at Bright Angel Trail. Actually we planed to stay two nights in the canyon but Phantom Ranch and campgrounds were fully booked half a year before. It was a big challenge for us therefore we began to exercise six month before to be physically fit for May. We recommend hiking sticks for the steep descent.