May Average Temperature: 43 to 73 degrees Fahrenheit
PROS: BEST TWO MONTHS (June) TO VISIT YOSEMITE!! You can put away your chains as of May 1st. Snow is melting big time; waterfalls are nearing their peak high flows and are spectacular. Valley is greening up; trees are blooming, wildflowers are out. High country trails are accessible below 7,000 feet; higher toward the end of the month. In most years the Glacier Point and Tioga Roads are open by Memorial Day Weekend. Half Dome cables go up the week before Memorial Day weekend.
Rain is very unlikely but not impossible. Temperatures are warm, but mosquitoes are not out yet.
CONS: Can’t think of any. Really, this is the prime time in Yosemite. The last two weeks in May and the first two weeks in June are TOP, PRIME Yosemite time! Crowds are picking up, but they’re not so oppressive that they are a distraction. If you’re planning any backcountry hiking be aware the rivers are high, fast and deep.
Average Temperature: 48 to 82 degrees Fahrenheit
PROS: BEST TWO MONTHS (May) TO VISIT YOSEMITE!! The entire park is now open. Unless it’s a very wet year with an unusually heavy snowpack, Tioga Road and Glacier Point Roads are usually open. High country is open up to about 8,000 feet. Tuolumne Meadows area is open.
Rain is very unlikely but not impossible.
CONS: Same as May. Mosquitoes are in full force by month end. Waterfalls are losing their full punch by month end and control burns in the park could put thick smoke in the valley.