Expanding

Siberia is definitely a wide expanse of openness, and what with the many hot springs situated in the area around the Baikal lake, one would expect a couple of hundred hot springs to be located in Siberia. At least.
Wrong. After much research there only seem to be a few. Or at least there is so little info available on internet. Or there may be hot springs still waiting to be discovered.

Cold Fame

Superlatives assume Siberia to be very cold. And apparently no place on earth gets colder than Oymyakon. Located 3 days drive from Yakutsk,

'Oymyakon boasts an average winter temperature of -45C, with a one-time world record low of -71.2C
...
Ironically, Oymyakon means “non-freezing water”, situated as it is to a nearby hot spring'. source

Even though this is ironic and might lead one to think that there can be no better way of illustrating the contrast by looking into more 'depth', alas the cold wins from the heat, at least in reporting on internet. Even such absurd news such as

'Nippy cows wear bras in Russia'

get a blog entry.

Possibly dinets.travel.ru refers to Oymyakon (Oimyakon) when focusing on orchids but mentions:

'Some rare and beautiful flowers, normally found only in Southern and Western Siberia, can be seen around hot springs in the uninhabited area between Suntar-Hayata and Verhoyansky Range. In this mountain chain, 3 times as long as Sierra Nevada, there are only two small villages and three mines. Hot springs do not freeze in winter, and I discovered a wintering population of brown dippers (Cinclus pallasi), diving in the water despite the frost'.

Possibly referring to the same, is the mention of Tjoply Kljuch (Tyoply Kljuch), which this Italian blogger refers to as having a 'fonte tiepida' (warm source). LP Thorn Tree also mentions:

'There's a small village called Tjoply Kljuch where there's a hot spring'.

By the way, Tyoply Kljuch is yet again mentioned by Wikipedia as a 'warm spring' on the Sea of Japan coast, north of Vladivostok, south of the Amur, somewhere totally different.

Complicating things even more is this blog entry mentioning that the near by Oymyakon, Tomtor, has a hot spring by wideview.it:

'A stream that never freezes, because of hot springs. The vapour, coming out continuously, freezes instantly over the trees all around, creating very bizzarre shapes'.

Funny

The most western hot springs of Siberia are located near the city of Tyumen. they are also more published and probably seeing a lot more visitors. 

There is a hot spring located just 5 km's from the city, named Verkhniy Bor and it

'... is well developed to accept tourists. Accommodation, meals are readily available. The water is highly mineralized having temperature of 45 degrees Celsius and cures many unhealthy conditions'. source

There are a few soak experiences on internet such as the blogs by englishrussia.com, nashural and this from Sergey Gershtein:

'There are hot natural springs that are said to be funny to visit in winter. It was funny indeed'.

He unfortunately fails to expand why they are funny. 

More photo's can be found on panaramio. 
The hot spring also has it's own website, aptly named vbor.ru.

Tripadvisor refers to this hot spring as Avan (I think) and the Russian reviewers give this hot spring four stars.

Verkhniy Bor, source

Gassy
Further away from Tyumen (27 km) is the hot spring of Sosnoviy Bor (website). Tripadvisor also hands out 4 stars here. 
It can also be referred to as Yalutorovsk.  Virtualtourist once had an extensive entry on the hot spring of what they referred to as Yalutorovsk:

'In some dozen kilometers from Yalutorovsk there is a hot spring. It is just in the forest, so the correct destination I can't say. In any way if you ask residents, they will tell you I suppose. It was funny to sit in the hot water when the snow was everywhere around. If you're in the center of the spring you may light it up because there is gas. It is not dangerous :-)'.

Now why has this link now disappeared?

Finally  some translated information on Tyumen hot springs, making the two hot springs clearer:

'A comfortable hot spring is located 11 kilometers from Tyumen - in the Upper Forest. There is a marble pool in the open air is filled year-round warm water. Pool length of 20 meters, a width of 6 meters and a depth of 1.5 meters is divided into two tracks, the temperature of water in them is different. It is surrounded by pines and ornamental palms, near the falls beautiful artificial waterfall.Near the hot spring are changing rooms and showers. This source is considered to be landscaped, as located near hotels, lodges and cabins for tourists, as well as all the amenities - gazebos, barbecues, and equipped with slides, ski and skate, skating rink, as well as a cafe, billiards, sauna, solarium, Karaoke and much more.Wild hot spring is located 30 kilometers from Tyumen. There are no facilities - it is possible to live in tents or go to the city'.

There is no infrastructure though, so pull up to the pool as close as possible. You’ll have to change clothes in a car and what’s more to run good 30 meters to the water in your bathing suit! That was a challenge with outside temperature -25. What’s more, one of my friends left slippers home and had to run barefoot. Needless to say, he sobered up immediately!

Sosnoviy Bor, source

Watercolours
So I hope I am not confusing everybody. As further west are hot springs near Turinsk by the name of Akvarel. Tripadvisor has also been here and the three reviewers have afforded it just three and a half stars.
Yet again there's a Russian language website through which I learn that the temperature is 35°C, it's 20 km from Turinsk town and renovations took place in 2013. Also this gem of info:

'A little history: In Soviet times, this place was Chekunova Hydropathic-worked doctors took patients. But something went wrong and this looked like a old abandoned building that was restored, rebuilt and opened a new set of watercolors'.

 More info can be had from this English website as well as the following picture:

Photo's from the past show a much more rustic and pleasant looking place. If I am not confused this from nashural concerns the same place?

Southeastwards from Tyumen (100 km) at most probably a town named Zavodoukovsk lies another hot spring, quite rustic. Named Beryozovka, this Russian website has some photo's:

Doesn't look too hot. But apparently hot enough, this hot spring came a a failure of the oil exploration industry. 

Two hundred km's northeast of Tyumen is another possible hot spring, named  Dubrovnaya (?) near the town of Tobolsk (source). It could also be named just Tobolsk ... (source). This is a website with more info.

Elsewhere this Russian website has a list of possible hot springs near Tyumen, unfortunately not all too clear. Probably this is the holy grail for this section. Can someone assist? Because this website mentions 7 hot springs near Tyumen, above are only 5 ...

On expedition

Nagqu
One of the biggest (bigger than California!) yet least traveled prefecture's of Tibet is that of Nagqu (alternatively Nagchu). This is all the more illustrated by using for instance flickr. The search term Nagqu only gets 83 hits, less than 1% of the number of hits Shigatse would get (figures from 2010)! Instagram gives 28 for Nagqu, 1428 for Shigatse ...!

Anyway, that probably means that researching the depth of information on hot springs in Nagqu will not be very rewarding. And complicating:  some websites placing Yangbajing hot spring in this prefecture (Yangbajing alone counts for 10.000 or so links). So when raking through the potential links for say Nagqu, it's quite difficult to find genuine Nagqu hot springs.

But still if one seeks, one finds. Dor Ji [1] mentions Gulug boiling fountain of Nagqu county. Another link to this hot spring is an article entitled, 'Chronology of the Gulu hot spring Cesium deposit in Nagqu, Tibet and it geographical significance'[2].Dor Ji also mentions a warm spring located in Nagqu town:

'The thermal water has temperature of 40-61C. A small scale geothermal power plant was also constructed here in the 1990s.
...
In addition, the Nagqu Geothermal Power Plant installed a 1 MW binary unit in 1993 but production was terminated due to serious scaling problems'.

The article also has a map with lots of red dots showing Tibet's more than 600 estimated hot springs! [Tibettravel.org puts an estimate of 1000+!]

A website promoting tourism in Nagqu (if allowed to come) once used to mention more than 200 soaking sites alone in Nagqu!

The following picture is taken from a Chinese language website. After translation it conspires that this is the first non-natural pool in Nagqu prefecture, it may well be called Lhomar and it's located 30 km's from Nagqu city.

Ancient art and soaking
Rongma hot springs, Nyima county find themselves often on tour programmes as there are also murals worth visiting:

'The picture on the stone can also change with the change of the season and time'.

There was once an expedition (?) to 'north Tibet" which expanded our knowledge on these springs:

'There are three layers in the hot springs. We stood on a piece of flat sand land, the first layer. Nearby there is a wading pool of nearly 200 square meters, with numberless spouting spring mouths. At the right of the pool, stalactites have accumulated over thousands of years, and one or two spring mouths can often be found in the middle or beside them. Some mouths have water spouting out, and some have no water but only a sound. At the right corner of the pool there is an earth hole, and the superfluous water of the pool overflows to an underground passage by this way and runs to the small river below.
There are some small spring mouths on the second layer. It is small compared with the spring pool aforementioned. In fact, each spring mouth on the second layer is able to spout enough water to make a pool. These spring mouths are obviously older than the spring pool. The stalactites there are solid and tall, in different shapes, some like a marmot watching the moon with its babies, some like playing monkeys and some like mother giving milk to babies.
The third layer is beside the small river. Tall stalactites have formed exquisite rockwork after being sculpted by superlative craftsmanship over many years. Lucid river water sometimes runs into a cave and flows on to another. There are two spring mouths in the river water at the cave mouth. The spring water spouting out creates an excellent sight with the tall stalactites.
Between the second and the third layer, there are two slopes, frozen now. With sunlight spreading on the ice surface, the colors change. The shape of each spring mouth is different; some only have one spring mouth, overflowing intermittently; the water is lucid and bright, but the sediment at the bottom is of different colors: green, pink, light yellow and milky white.
Rongma hot springs are still in a pure natural state. Except for two stone pagodas and sutra flags beside the upper wading pool, there is no man-made mark. According to local people, nobody goes there except locals washing clothes'.

Rongma hot spring photo by Single Singer

One must note that Rongma hot spring is quite unique:

'The Rongma Hot Spring is a collection of naturally warm springs that span over hundreds of kilometers'.

Exposing skin
Also in Nyima county is the hot springs of Wenbo; the excellent aforementioned expedition of north Tibet describes:

'The altitude of the hot spring is 4,516 meters, a little lower than Rongma hot springs, but the climate is much worse. The spring mouth is halfway up the hill. There are only 100 meters from our parking place to the spring mouth, but we spent 20 minutes getting there. We actually panted three times for every step.
There is only one spring mouth, as large as a bowl, overflowing water. Local people dug out two hollows below, one large and one small surrounded by gravel. The larger one has a tall and glossy wall with a small hole for the overflow, available for three people to bathe at once; it is especially for men. The smaller one is especially for women and the wall is less than half a meter. Standing in the men's pool, one can see everything in the women's pool where not only the cold wind cannot be prevented but also privacy is nil.
I could not resist the inducement of that green pool, and began to take off three cold-resistant military overcoats. Once the skin was exposed to the cold wind, it was so cold that I felt the bones hurting, which is unimaginable for people who have never been to northern Tibet in winter. When stepping into the pool, it was so comfortable that I felt each pore was breathing.
The shining sun is just overhead, and the ultraviolet radiation shines on the skin by reflection from the water surface like a lot of small needles. I tried to hide my body under the water and hide my head in the shadow of the wall and began to relax with eyes closed. The northern wind howled outside the wall; the scene inside the wall is exuberant, stalactites covered by green lichen, and the spring water rushing into the pool, making the sound of "large and small pearls falling on a jade plate".
Gongzha told me that during the Bathing Festival every year all people living for hundreds of miles around come here to bathe. The bathing rules are very strict. For example, the first bathing duration is 10 minutes, the second 15 minutes, and the third 20 minutes, and so on until you reach the longest duration you can bear. And then, one should reduce the time by five minutes one after another until returning to the beginning.
During the Bathing Festival every year, as there are so many people, an old Tibetan doctor will arrange the time depending on individual person's situation, such as 15 minutes or half an hour, and everybody will step into the pool by turns. It is said that by bathing for a week during the Bathing Festival one will not catch a cold in a year.

Hissing
As if this was not enough, the expedition to Nagqu as described in Tibetmagazine features the hot springs of Lhaya, however it's unclear where exactly they are other than on the border between Shigatse and Nagqu:

'Lhaya Hot Spring is in the river valley beside the road. From far away we saw mist curling up in the valley and heard the "hiss" of the spurting spring spreading far into the valley.
There are two springs in the center of the river, with one discharging directly into the river, the spring water creating a circle of some one square meter like an umbrella on the river surface; the other one is what people call a 'multicolored spring'. In center of the river, stands a round stalactite some 100 cm higher than the river surface that emits different color from the sun's rays. The spring water spurts out from the middle of the stone, as high as about one meter, and is very beautiful. Many fish without any scales swim around the spring. ... The spring is in the center of the river and access is impossible, which is a pity'.

According to wikipedia the village of Dongqiao (Amdo county) is noted for it's hot spring of Jipu. But that's all what the internet will reveal on this subject.

Notes:
[1] Dor Ji (2008) Geothermal Resources and Utilization in Tibet and the Himalayas. Presented at the Workshop for Decision Makers on Direct Heating Use of Geothermal Resources in Asia, organized by UNU-GTP, TBLRREM and TBGMED, in Tianjin, China, 11-18 May, 2008.
[2] Zhao Yuanyi , Zhao Xitao , Ma Zhibang & Deng Jian [unknown] Chronology of the Gulu Hot Spring Cesium Deposit in Nagqu, Tibet and It Geological Significance. Institute of Mineral Resources, CAGS, Beijing, China

Inadvert

Though Tajikistan's hot springs are mostly defined by those found in the Wakhan and Pamir (link), there are more to be found in the rest of the country. Unfortunately mot of these have been developed in to Soviet style health spa's thereby diminishing the experience and it's connections with nature.

At the carwash
Nearly 100km to the east of Dushanbe (capital of Tajikistan) is the hot spring of Obigarm. The area is home to 

'... tens of hot mineral springs (source)'.

An experience:

'The one place I went had a pool of the hot mineral springs and it was all that I could do to be in there for 2-3 minutes. Another place I went had this funny looking shower contraption. Basically it looked like a carwash for people. It was built form like 6-8 long pipes that stood up at about shoulder length and had holes that sprayed water towards the inside. Basically, you were supposed to stand in there and let all the mineral water hit all over you body. It results in a kind of water massage'.

More experienced info here.

What the baths may well look like (source).

Disgust
Not to be confused with Obigarm, Obigarm-Khoja is due north of Dushanbe, higher in the mountains. 

And though one associates soaking with pleasure, it seems here the soakers are patients:

'This is a large comfortable health center for 700 people. There are several sanatoriums and health care buildings. One can also find here a special complex of "paroemanatorium" - where vapor of set proportion and temperature is used for treatment. All necessary conditions and conveniences are at the patients' disposal after medical procedures'.

For a full back ground look at this website complete with Soviet style 'resort'. 
An experience:

'The main resort, half painted in garish yellow, frowned upon our intrusion, whilst the private resort begrudging bestowed us with a tour and tinged sheets. In a mouldy changing room wearing inappropriate underwear we wrapped in linen, and skated across the floor in borrowed pool shoes to the bath. Thankfully, the pool of eternal youth was shrouded in enough steam to hide all the flaky skin, and sizzled like a cauldron upon entry. I dipped in, and then jumped out before all my hair bleached and decided to enter the steam room to recover. However, this proved too acidic for my tender lungs, no health warnings here, in fact you are actively encouraged to breath in this toxic gas for up to twelve minutes and repeat the process several times to ensure all your lung tissue is contaminated. In an attempt to recover from the ordeal I hung out of the window and peered at the snow-capped mountains, whilst inadvertently venting the room to the disgust of the other guests'.

Sludge
There's not much info on other hot springs, what follows are a couple of snippets.

'Shohambary sanatorium operates at the territory of Hissar District. Its mineral water temperature ranges from 37 to 42 C. In summer time, besides in-patients, the sanatorium also hosts out-patients. Digestive system diseases are treated here'.

Also known as Shambari, Shaambary or Shokhambari, more info here.

A couple of mentions of Khavatag:

'Sanatorium "Khavatag" is located in the Fergana valley, 630 m above sea-level, on the northern foothills of the Fergana range, 25 km to the north-west of "Ura-Tyubeh". "Khavatag" means "mountain air". Hot mineral waters of "Khavatag" are useful for treating diseases of motorial organs; functional disorders of the Central Nervous System and particularly those of the peripheral nervous system; gastric and intestinal, skin and gynaecological diseases'.

'In 1948, a hole of 1,300 meters deep was drilled by geologists in Khavotag, Ura-Tube district. The hot water coming from the drill-hole was proved to be curative for many diseases. Now, the healing water of Khavotag is used for the treating many muscle and bone diseases, distal nervous system and dermal problems'.

Source

Yavroz hot springs gets a mention:

'50km from Dushanbe, (25km from Vahdat) in Romit Valley, there is the Yavroz recreation area at 1,150m above sea level. It has a thermal spring containing silicate, boron, hydrogen sulphide, and radon. The water of the spring, located 2km from the sanitarium, is medicinal and is used for treatment of diseases of the musculoskeletal system, peripheral nervous system and skin'.

Sarob gathers one mention here: 

'Health-improving hotel "Sarob" is balneological complex, that has a number of medicinal health-improving treatments: radon steam, radon pool, radon bath, circular shower, Charcot's douche, intestinal irrigation, gyneacological irrigation, therapeutic mud-baths, paraffin, ozocerite, light bath, darsonvalization, electrophoresis, ultrasound, vertebral massage "Armed", vibratory massage, hand massage, vertebral traction'.

Then on Zumrad hot springs:

'The main natural therapeutic factor is thermal (upto 26°) methane, chloride sodium sulfide boracic waters (mineralization 85—130 g/l). Deposit of mineral water Obishifo (discovered in 1968) is 39 km far from Zumrad town to the west. Water is used for bath. Along with the mineral water as a natural therapeutic factor the sulfide sludged mud is also used'.

Other of Tajikistan's best-known springs are: Anzob and Tashbulak. Unfortunately no other details? Possibly cooler soaks?