Mt. Whitney Portal Store & Hostel Forums General Mt. Whitney Portal Store Message Board Weather predictability

I know it's a mtn and anything CAN happen but is it quite common for the weather toward the top to be dramatically different than below? I'm talking late June/early July. At Shasta, for example, it's not uncommon for it to be in the 80's on the ground and 20's or teens above Helen Lake. Also, is wind a huge factor on Whitney like with Shasta? I know thunderstorms are a threat but I'm trying to get my hands around the other potent weather systems on the mtn. I'm trying to figure out how much to bring up on the hike itself based on conditions at the bottom (or day before temps). We'll be doing a one day hike.

Of course the weather can vary from one day to the next. That time of year my biggest concern is the afternoon Thunderstorms. By 10-11 am you will begin to see storm clouds forming. After noon it can rain on the top every day, clearing up again by late evening. This pattern seems consistent every year from sometime in July to late August.

This is because of hurricane moonsoonal currents coming up from the gulf.

So, leave early and plan on being on the summit before noon. That way you will be on your way down if it happens.

Many times I have been around 12000 feet and had great weather, only to get to the top in a developing storm cloud.

You can get some idea about the weather a day or two before by looking at reports for surrounding areas but that will only be marginally accurate when applied to Whitney. I've been surprised often.

It can get windy or cold but afternoon thunderstorms are the most common phenomenon. Seems like you can almost set your watch by them and July is especially bad. They usually form up in the afternoon and around 2pm or so do their thing (lightening, rain, and hail) and evaporate as evening sets in. The best bet is to get an early start. For July I usually just pack a light sweater and a rain shell. It usually starts raining up top first and often doesn't make it down to the valley. Once the storm starts to let loose you'll be forced to descend. It's not uncommon to get rained on up higher and then get back down to the Portal only to find it dry down there.

It's also not a bad idea to carry an emergency poncho (the thin disposable ones), space blanket, and/or a trash bag.

-Rick

The Sierra is very unpredictable. In recent years about 3/4 of my trip I have seen various types of weather, however, in all my summit trips to Mt. Whitney I've seen an hour of rain....go figure.

You state this is a day trip but are you planing to summit before dawn or just a regular 2 AM start? This might change what people would suggest. If this were the case I'd have some extra insulation and a 2nd pair of gloves.

You have to prepare for cold, wind and rain.