I never call off a trip for weather but I don't do stupid either.
Many moons ago, we backpacked out to Long Lake with the idea of doing Cirque Peak that day. When we arrived at the Lake, we heard "crack-boom". No summit that day, we were stuck on east side. As we sat around camp during the storm, we saw a guy with shorts and t-shirt running down the trail from High Lake being pelted by hail.
The following day we were up to and off the mountain be 8 AM, and were being rained on as we broke down camp before noon. And there were many big "crack-booms" as we motored through the South Fork Drainage back to Horseshoe Meadow.
You may have to alter your plans to deal with the weather and you may not reach your planned on destination but you will have a worthwhile trip whatever it ends up being...as long as you are prepared for the worst.
