The arrival of mosquitos corresponds to the time of snowmelt and the presence of areas of flatter terrain with standing water. A five-time PCT thru-hiker put the average start of the mosquito season in the Sierras at June 18. This year the snowpack is currently at about 70% of average, so this date will probably come a bit earlier. No matter what I do, I'm going to end up in the High Sierra at the start of the mosquito season, which will likely extend another month and a half through northern California and the Oregon Cascades. Yikes.
Here I'll lay out my mosquito protection plans in three categories:
1. Stationary (protection during the night and during long rest stops)
I am going to make a long noseeum tube out of a swath of netting 10' x 6.5', with drawcords on both ends that can be accessed from inside the tube. This will enclose my hammock and can be pulled over me in a sitting or standing position as well. My experience is that a headnet is far from adequate stationary protection, since you can't eat with it on (!) or expose more of your body.
2. Mobile (protection while walking or taking short breaks)
I will have a mosquito (not noseeum - the weave is too dense, and you can't see well enough through it, and it gets stuffy!) headnet, and am considering sewing "hand nets" which are basically just net bags with elastic for the wrists. I can wear my wind layer, which is mosquito-proof, and mini-gaiters, which cover exposed ankles.
3. Emergency (if the above is not sufficient, or it's too hot to wear a wind layer)
A bottle of 100% DEET.
Also of critical importance is to not sacrifice more important physiological needs - such as food, water, rest, and defecation - because of mosquitos. I may plan regular stops where I quickly set up my hammock and bug net and get in to snack, rehydrate, and rest.