Re: Is it reasonable to expect mosquitos to not be a problem by July this year?

Yosemite vets, in snow years this weak is it reasonable to do trips in the high country in July without having to deal with mosquitos? How has it been in past similarly low snow years? I just can't believe how weak the flow looks on the Yosemite Falls webcam already and I'm very tempted to reschedule a late August trip for July. It's hard to even find snow now on the Sentinel Dome webcam. I wonder if Conness is likely to be doable without snow by early/mid/late July. Thanks for all the help you guys have given me.

My rule of thumb...the mosquitoes end when the wildflowers wilt.

The mosquitos are already out, albeit in small numbers. I did Clouds Rest today and they were not an issue except when I stopped to change water bottles or adjust gear. In my experience of 33 years hiking in Yosemite, I have *never* not seen mosquitos be an issue in July. Solution? 100% Deet. That minimizes their annoyance to an enormous degree.

And you're right about the low snow year. The trails are as dusty and dry as they are in late August. I worry about drought. I haven't seen the High Country this dry in May in decades.

Just back from Tuolumne Meadows...here is the skeeter report..
Sunday - Snow on the ground - zero skeeters
Monday - at Polly Dome Lakes at noon saw 2 skeeters
Tuesday we were up high - saw one skeeter all day
Back at the car at Cathedral Lake TH at 11 this morning - and in the 5 minutes from packs off until we got in the car there were somewhere between a thousand and a gazillion skeeters, half of which made it into the car. (But it was pretty!)

I am guessing that the skeeters will be mostly dried up, like the flowers, by late July..but maybe that's optomistic thinking since I have a permit for a July 26 start at Tuolumne.

More on the recent trip later.

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Bearproof
I am guessing that the skeeters will be mostly dried up, like the flowers, by late July..but maybe that's optomistic thinking since I have a permit for a July 26 start at Tuolumne.

We'll see, but your 'late' qualifier seems key to me. I'm not ready to suggest, for example, that someone who requires a largely mosquito-free trip consider the July 4 holiday weekend in the Yosemite high country.

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ttilley

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Bearproof
I am guessing that the skeeters will be mostly dried up, like the flowers, by late July..but maybe that's optomistic thinking since I have a permit for a July 26 start at Tuolumne.

We'll see, but your 'late' qualifier seems key to me. I'm not ready to suggest, for example, that someone who requires a largely mosquito-free trip consider the July 4 holiday weekend in the Yosemite high country.

Agreed. You gotta have qualifiers...there will always be some mosquitos..you gotta expect that. The question is whether there will be "some" or "too many" and there are so many variables that can affect the situation between now and then. I will have a more definitive answer on July 26 if that helps.

Thanks guys. I figured they might be hatching earlier and dying off a month ahead considering how the snow seems to have done so.

The main determiner of the end of mosq hatching is the lowest overnight temperature. I think the magic number is 34 deg F. Once the temps dip below that consistently, the hatch stops, and you won't see them shortly. Labor day is a rough guide, but elevation matters, as does latitude, and local conditions.

I was near the Domelands above Isabella last week, at 7K, and they were definitely out, although not aggressive.

You guys should check out the use of Permethrin on your clothing. Dramatically changes mosq attack rate and bites. Really cuts the need for DEET on the skin.

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KenM

The main determiner of the end of mosq hatching is the lowest overnight temperature. I think the magic number is 34 deg F. Once the temps dip below that consistently, the hatch stops, and you won't see them shortly. Labor day is a rough guide, but elevation matters, as does latitude, and local conditions.

And overnight temps are also a good gude when mosquitoes will START to hatch. It's not about water levels, but more about the temps of the high country. That's why for me mosquitos have never been a major problem in the high country of Yosemite in May, even during low snow years – because the overnight temps were still too cold for widespread hatching of their eggs. But come June and then July, watch out! Low snow year or high snow year, there's usually plenty of mosquitos to contend with from mid-June through July.

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KenM
The main determiner of the end of mosq hatching is the lowest overnight temperature. I think the magic number is 34 deg F. Once the temps dip below that consistently, the hatch stops, and you won't see them shortly. Labor day is a rough guide, but elevation matters, as does latitude, and local conditions.

I was near the Domelands above Isabella last week, at 7K, and they were definitely out, although not aggressive.

You guys should check out the use of Permethrin on your clothing. Dramatically changes mosq attack rate and bites. Really cuts the need for DEET on the skin.

I concur. Works miracles for me.

May is too early for mosquitoes above 8k. And below that they can easily be wiped out when a cold storm comes down from the northwest like the one that just blew through on the holiday. One can predict there will be less than normal because there will be less snowmelt once June arrives and temps are not dropping down below freezing anymore. However there are many streams and rivers where things will stay wet well into August. For instance you could guarantee hiking from Tuolumne Meadows up the Lyle Fork will have some squeets well into August.

The better strategy for all you shorts and t-shirt types is to learn how to dress more appropriately during mosquito season and not be afraid of using DEET. We always hike more during mosquito season than late season because it is more scenic and interesting. Though squeets are a nuisance, we are not really all that bothered unless they become swirling clouds and usually get just a few bites and those are almost always on my hands and wrist after sticking them in water for whatever reason that rinses off the DEET.

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http://www.davidsenesac.com



Edited 1 time(s). Last edit at 05/31/2012 01:50PM by DavidSenesac.

I prefer to hike in lightweight convertable pants and ventilated long sleeved shirt, and a cap with a havelock, (I like the Outdoor Research sunrunner). I also use Warmers half-finger sun gloves to protect my hands from chafing from trekking pole straps. Hot weather no skeeters, roll up sleeves and zip pant legs off. Treat your clothes with permethrin and your skeeter/sun exposure is minimal, just a small area on your face. Not so much to wash before you get in your bag. IMO 100% deet is overkill. Ultrathon 34.34% hits the sweet spot and works great.

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rob
Ultrathon 34.34% hits the sweet spot and works great.

It didn't work on biting flies on the High Sierra Trail for me.