I really don't think the mosquitos are that big of a deal and would much rather deal with them than the potential cold weather in September.

I guess it's a matter of personal choice....

I was in Eastern Siberia in mid September to early October, camping with friends. We had no winter gear but always made large fires in the evenings and were never cold. Nights were about -10ºC and there was some snow later on, but the days were perfect with mostly clear bluie skies, some of my very favourite travel memories. There were no mosquitoes.

This year I drove across Russia south to north (Dagestan to the Barents Sea) and there was not a single day where I could sleep outside as the mosquitoes were unbearable. Even if you don't care about getting bitten (they don't carry any diseases after all), the noise and the fact that they fly into your eyes and face all the time, meaning you need to wear a headnet, is infuriating, and was the only downer on an otherwise perfect trip. I did some trekking in the North Urals and was bitten 50+ times through two layers of clothing. There is also the possibility of contracting Lymes disease or tick-borne encephalitis from ticks. Wearing 50%+ DEET works well, but it's not the nicest stuff to smear on yourself, and you need to keep re-applying if you sweat or swim.

Next year I'm driving to Magadan in September / October.

I would say that I am driving a car, so once on the move cold is not an issue, but surely you can get decent riding gear. Also, autumn in Siberia can be quite fickle and unstable. But anything is better than the constant, infuriation of those damn mosquitoes.

Just my opinion...

EO

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EurasiaOverland a memoir of one quarter of a million kilometres by road through all of the Former USSR, Western and Southern Asia.

Hi!,
Im doing the reverse; from West to East next year (2016). Good to know what to expect either the mosquitos or cold. Its a personal choice. I am planning to start from Holland (where my bike is parked now) somewhere in July towards Moscow then all the way to Vladivostok with a short diversion into Mongolia.
Anyone care to team up? Im riding a 2008 KLR650.

Amzah

Yes, its a personal choice, but I'd like to mention two other things so that people can make the correct choice for themselves:

1) it sound like eurasiaoverland camps a lot, in which case, sure, you'd have more exposure to mosquitoes. I rarely camp and personally haven't had any big issues with mosquitoes even when I did camp.

2) it sounds like eurasiaoverland was in a car, not a bike, so cold is less of an issue. while you can dress up against cold to some extent, personally i dont want to ride if there is any real threat of snow/ice on the road, as there would be in Siberia in October (if not earlier).

True on both counts, I've no idea what it's like to ride a bike in the cold or snow (even colder than usual I expect!). That said I think leaving Vladivostok early September and taking let's say one month or thereabouts to get to Moscow on the conventional route, you'd be pretty unlike to get any snow.

I thought camping was 75% of the fun of crossing Siberia

Depending how slowly you're travelling I might pass you on my way from Netherlands to Magadan next September.

Don't leave the trip to Mongolia too late; that is one place where you really don't want to suddenly get snowed in... all the tracks completely disappear!

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EurasiaOverland a memoir of one quarter of a million kilometres by road through all of the Former USSR, Western and Southern Asia.

September is generally OK, although if you're heading up toward Magadan, everything I've seen indicates that it can be cold and snowy up there by the end of September.

Once you're into October I think it gets much more dicey; while this is an unusual snowfall, this year Omsk got 40 cm of snow overnight on Oct 22:
https://www.rt.com/news/319351-siber...l-omsk-record/

Obviously, on a moto even if it were 5cm instead of 40, you could have a problem.

Anyway, best of luck.