“I’ve hiked to/from Phantom Ranch in the summer. The inner canyon in that area can get to 120+ degrees. What type of air temperatures should we expect on an early July trip in the Upper Canyon?”
This is a great question from Alan. Those of you who know the canyon or who follow our blog know it definitely can get HOT in Grand Canyon during the height of an Arizona summer. Temps higher than 120 degrees are not unheard of, especially in stretches of the canyon where dark rocks absorb and radiate the heat all day long. Our Upper Canyon trips begin in Marble Canyon and end at the Upper Gorge/Phantom Ranch area. The Gorge is a stunning stretch of the canyon filled with gunmetal-gray Vishnu schist — one of my favorite rock layers — which DOES get hot. However, because the Upper Canyon trips end at the beginning of the Gorge, these trips don’t see temperatures that are quite as extreme as those in the Lower Canyon, which has a lot more volcanic rock.
Photo: A beautiful, overcast August day in Lower Grand Canyon.
We can’t predict the weather, but we do know from experience that the AVERAGE high in the inner canyon is about 105 degrees for July. The average low is 78 degrees, and the precipitation for the month is .84 inches. (Less than 1 inch of rain might not sound like a lot to some of you but, for those of us who live in this desert, we know that’s actually quite a bit! The only months that get more rain than July are August and September — and they don’t get much more.) If you are doing a trip between July and mid-September, when temps are highest, you’ll be very glad if you get some afternoon cloud cover. Mid-summer is our monsoon, or rainy, season … luckily. You also will really appreciate the cold (48 degrees) river water on a mid-summer trip.
The best way to check temperatures for your upcoming river trip is through the NOAA website. Check the temperatures at Phantom Ranch, which is at river level, rather than at the North or South Rim of Grand Canyon. Temps between the rim and the river can vary quite a bit. Regardless of whether or not the forecast calls for rain, come prepared for a STRONG sun!