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

A group of 4 of us are planning a day hike next weekend, we plan to start at midnight. I am hoping some people here could give us some insight on weather for the hill, mostly what kind of temperatures we might expect. Curious if it is typically below freezing at trail camp at sun up? I'm telling my group to be prepared for cold, but wondering HOW cold? Any weather infomation would be appreciated. Thank you.

Weather at 12,812', 11,290', and 8,689' in the Whitney Zone.

There's nothing special about these altitudes. They're just what the weather service has available. To use them to estimate Trail Camp (12,000') temps, figure 1/2 way between the 12,812' temps and the 11,290' temps.

For example, as of the time of this message, the forecast for Trail Camp low temp next Saturday night would be halfway between 37ºF and 42ºF, which is about 40ºF.

From the above data, the temp drops roughly 3ºF for each 1000' of elevation gain. Thus we can roughly estimate the low temp at the summit to be 32ºF next Saturday night.

I have found these types of readings at NWS to be inconsistent, some lower temperatures at lower elevations. I find using the NWS Bishop and Cottonwood Report Stations temperatures then extrapolating to be more accurate.

YMMV

But aren't the Bishop and Cottonwood temp readings you mentioned real-time and history readings, not forecasts? Also, how would you extrapolate to other altitudes? And just because the NWS readings indicate sometimes a temp inversion doesn't mean it isn't correct, unless temp inversions are not possible in the Whitney Zone. Is that the case?

Maybe I should clarify something I did in my rough calculation for the summit temp. I only used the rough estimate of 3ºF per 1000' in extrapolating from 12,812' to the summit because the data happened to be going that way on that particular night. It was fortuitous that there was some rough order to the temp drop with elevation gain in the forecast for that night. Even so, I think it's only a best guess.

wbtravis 5152, You have a lot of experience in the Sierras so I have to respect your methods. What would you estimate for the low temp at Trail Camp next Saturday night?

As you might expect, this has been long studied by the FAA for pilots to understand temperature vs. altitude. The answer is that the standard temperature lapse rate is 3.5 degrees F per 1000 feet. However, several variables can affect this, particularly on big mountains like Whitney.

Here's a thread that discussed the temperature lapse rate of 3.5ºF/1000'. Doesn't seem to be very reliable for estimating temps on mountains. http://www.whitneyportalstore.com/forum/ubbthreads.php?ubb=showflat&Board=1&Number=2732&Searchpage=1&Main=301&Words=%26quot%3Blapse+rate%26quot%3B&topic=0&Search=true#Post2732

Thank you ALL who have taken the time to post information.

It is all greatly appreciated.

Barring any frontal passages or monsoon moisture coming up, we have a pretty good idea of the temps. we should be expecting.

Thanks

Bill

Weather reports are bringing some moisture up this way from the old Hurricane Dean later this weekend.

Is anyboby hiking Sunday through Tuesday worried about the weather??

Or is it just me???

Bill,
I'm keeping an eye on Dean. We have a small group with permits for Monday. We won't push it if there is lightning activity or any other hazard from Dean. Still heading to the Portal just with the understanding that our trip may be only be to that point.