The weather on top of mt. Shasta this year ranges between 12 and 30 degrees Fahrenheit at 14,180 feet in elevation this time of year

 https://www.shastaavalanche.org/weather/forecasts/current-summitplateau

Mount Rainier

14,411′

Mount Whitney

14,505′

Mount Hood

11,250′

also as you can see mt. Shasta is within a few hundred feet in elevation of both Mount Whitney and Mount Rainier