All, please excuse me for asking a silly question but my curiosity has the best of me:

Are Sierra mosquitoes less aggressive in early season? If so, why??

Was up by Sawmill Pass this past weekend and encountered swarms of mosquitoes near all the water sources...but got away with only a bite or two. I was able to observe a couple of them land on my arm and then fly away...completely devoid of any of my precious blood!

Beyond my anecdotal account, last night I read in my Sierra High Route guidebook something to the effect of...early season may be more pleasant before mosquitoes turn aggressive. Could probably quote it exactly when I get home.

Anyway. Just curious.

I've heard it takes a while before they learn their mission in life.

LOL...so I must have encountered the mosquito equivalent of angsty teenagers last weekend. Better watch out when they hit their college years and start binge drinking.

I was in mobs of them 3 weeks ago and no bites. Now I'll come out looking like a sci-fi freak.

Some time I feel like if there's a mosquito within a mile of me guaranteed it will find me. Some years ago in Yosemite Valley I was eaten alive by them, the first day. The second day no sign of mosquitos, and a few we saw didn't bite. I told my wife the little devils are so full from the first day they can't drink another drop.
Is it possible that an animal like a deer 0r something must have gone by before you got there?

I'm glad other people have had similar experiences and I'm not totally losing my mind. After some googling it seems this topic has been beaten into the ground pretty good, although most discussions seem to focus simply on the arrival of mosquitoes each summer, not necessarily their voraciousness.

I actually did spot a couple deer grazing in the meadow where the mosquito density seemed to be highest. Although they pranced off into the woods pretty quick and seems just a couple deer would not satisfy an entire hoarde of the buggers.

The 'internet science' on this topic is pretty highly developed, haha. One poster suggested that mosquitoes breeding in transient puddles and the like are programmed to feed and reproduce more quickly before the water dries up. Others suggest warming temperatures increase their activity level, which is consistent with my experience that in early season they're just kind of slow and dumb.

Maybe on the rest of my trips I'll go shirtless and conduct a full-on highly controlled scientific study. Go up the same trail at the same time of day for a few weeks, take a bunch of temperature/humidity measurements, catalog species, count bites and severity and solve this problem once and for all. LOL

I camped at First Falls in the North Fork of Big Pine Creek over the holiday weekend and day-hiked to the Palisade glacier from there and was likewise amazed that I did not get eaten alive. I brought 30% Deet wipes and a small Deet spray bottle but hardly saw any mosquitoes even though the walk-in campground at First Falls is right on the creek. I couldn't believe it. They were noticeable at Lon Chaney's cabin, but still not nearly as bad as I have experienced there in years past.

Trump deserves credit for this one. Make America great again even less mosquito bites.

Thanks Norris, your story helps prove my sanity which is somewhat surprising, haha. And I'm hoping to head up that way soon so the update is appreciated.

mrchad, an investigation is in order. We all know there are tapes and the smoking DEET candle is sure to surface any minute now. The mainstream rangers cannot suppress the truth indefinitely ....