It’s always a good idea to check the weather before a trip to the mountains this time of year, so I did. A high of 76 degrees sounded pretty nice and a bit like wet-wading weather though I still considered taking my waders on Saturday’s trip to the upper Stanislaus. But maybe lost in the glorious image of wet-wading under the warm afternoon sun, which caused me to leave my waders at home, was a key element of basic meteorology and planetary science.