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#45532 - 03/24/16 03:48 PM Historical Weather Averages
Frankie Bones Offline

Registered: 05/21/15
Posts: 10
Loc: Los Angeles, CA
Happy Spring!

I've been trying to locate historical weather averages for Whitney portal + summit, but have thus far been unsuccessful. I have explored the weather options located on the left sidebar, but could only find real time forecasts. I'm trying to find historical averages for the second half of August for the last few years -- any ideas on where they can be found?

I've done traditional google searches already.

Thanks again.
Frankie Bones

#45539 - 03/24/16 10:51 PM Re: Historical Weather Averages [Re: Frankie Bones]
Steve C Offline

Registered: 09/22/09
Posts: 7524
Loc: Fresno, CA
FB: since the weather forecasts for both those locations are estimates and not actual measurements, I don't think records are kept at all. It would be really helpful if a weather station were installed at the summit hut, and I even tried to discuss it with a Sequoia N.P. official some years back. The response I got was that it would just be that much more "junk" in the backcountry. I have the feeling I may have been talking to the same person who told me he thought people couldn't have a true wilderness experience if they carried a satellite tracking/locator device in the backcountry.

#45553 - 03/26/16 06:47 AM Re: Historical Weather Averages [Re: Frankie Bones]
Bob West Offline

Registered: 11/13/09
Posts: 828
Loc: Bishop, CA, USA
The NOAA website has a lot of historical information, but requires a certain amount of "drilling down" into the menus.

Here is some historical data for Aspendell,CA, near Bishop. Aspendell is at 9,000+ feet. By adding @ 5,000 feet you might be able to guess-t-mate conditions at the portal and summit of Whitney:

Looks like a complicated project!

I will try to find some historical snow pack data for you. is some data for the Big Horn Plateau (Kennedy Meadows area), which is south of Whitney:

First, the "Snow Course" menu will help you find the location of interest. Each area has a three-digit code, which is used for searches. The Snow Courses are areas of major water shed interest (drainages). The snow sensors and physical surveys are usually in meadows, not on mountain summits like Whitney.

Have fun.

#45556 - 03/26/16 03:23 PM Re: Historical Weather Averages [Re: Frankie Bones]
Steve C Offline

Registered: 09/22/09
Posts: 7524
Loc: Fresno, CA
Second half of August... Are you planning a Whitney hike in that period this year? Here's what I would do: Watch the weather forecasts in the two weeks before the trip. It will be either dry and perfect weather, ....or thunderstorms.

August, in my mind, is the most prevalent time for t-storms. If there is any sort of system blowing in from the south (they come in off the Pacific Ocean over Mexico, and then head northward. In that situation, there are most often thunderstorms with even hail and cold on the summit. These are the heaviest storms in August.

The second situation is without the storms out of the south. If there is a hot and more humid pattern west of the Sierra, huge thunderheads can build over the Sierra every afternoon. Those pretty much always dump in the afternoon in the mountains. They aren't uniform -- some areas of the mountains can be missed.

In either of the above weather patterns, you should plan on carrying rain gear when hiking Whitney. Otherwise, only if the weather is steady and dry could you skip the foul weather cover. (but I would at least carry a big trash bag to use in an emergency).

#45692 - 04/07/16 09:54 PM Re: Historical Weather Averages [Re: Steve C]
skyrooster40 Offline

Registered: 02/15/16
Posts: 1
Loc: Oak Park Ca.
Good info on the weather. I heard it is a good idea to summit before noon due to Thunderstorms. We are doing a Whitney day hike on Aug. 24. Any thoughts

#45705 - 04/09/16 09:29 AM Re: Historical Weather Averages [Re: skyrooster40]
spitzer Offline

Registered: 03/14/16
Posts: 5
Loc: USA
There's a third possibility for the weather that time of year. That's the Sierra monsoon. The moisture comes from the southeast and sometimes sits over the Sierra for a week or more. It can create afternoon thunderstorms but when it's strong enough it will rain all night and into the next morning as well. Rain rain rain rain. A couple of years ago we had a really good one in late July through early August.