The trick is simple: dress in layers! As for the autumn season, the trick is the same here too. Even if with lighter garments of course. I know that the preparation can often last as long as the outing itself, but it's the price you pay to have fun even with temperatures close to 0. In MTB you usually tend to dress less than on the road, precisely because of the lower average speeds.
WINDPROOF IS NOT THE ULTIMATE SOLUTION TO THE COLD
Be careful not to make the mistake of dressing too much and using non-breathable jackets: this is the mistake that every beginner biker makes, perhaps by wearing windproof jackets that are not very breathable. Ok, they are perfect for downhill, but when you start pushing on the pedals (and therefore producing heat) not being able to expel it will lead you to rediscover the same sensations you feel during the sauna on weekends in the mountains.

INCIPIT
Naturally, experience and our level of training are very important: the most trained bikers (generally) are less cold because they are able to keep the intensity high even for several hours of training. The beginner biker, on the other hand, is unable to maintain a high pace (except for a few tens of minutes) and therefore cools down. How to do? Here are our clothing tips for each part of the body.
HEAD/NECK
Most heat loss occurs through the head. The aim is therefore to keep her warm, also to avoid severe headaches on the return (for those who suffer from them). But be careful not to cover up too much: our advice is to use a thin head covering, for example the BUFF brand (see photo below). By extending them you can also cover the ears, another very delicate point. Always present is the principle that, if you dress too much, you will get wet and suffer from the cold even more (as well as not being able to "perform" in the best possible way). Note: some bikers find it essential to use these garments even in summer, to avoid having sweat in their eyes.

BUST
And here comes the principle of onion dressing. In this area we find the 3 layer rule: dry, warm and protected from humidity.
UNDERWEAR: garment in direct contact with the skin where a warm but breathable garment is needed (it is winter). Breathability in this first layer is fundamental: if we wear a heavy, hot and non-breathable garment, you risk having the opposite effect as soon as you start to sweat (i.e. being cold).
LONG-SLEEVE TOP: in this second layer you have to use the right garment for when you are under stress. Imagine yourself going uphill under stress: you certainly don't look good with a fleece on, right? So he's wearing a piece of clothing that is sure to make you feel a little chilly as soon as you get out on the bike.
MANTRA: if, after leaving the garage at home, you are nice and warm, you don't have ideal clothing but you are overdressed! Being a little cold (not too much) is not wrong, on the contrary.
It must be a technical shirt with a weight level of at least 200g, but here it is difficult to give universal advice: it depends on your resistance to the cold and your level of training (see initial incipit). The important thing is to keep in mind the Previous MANTRA.

A heavy wool sweater is not really suitable for going out on a bike 🙂
JACKET / SLEEVELESS: and here is the final piece, the one that saves you if the situation gets colder, or if there is a descent, if the pace drops or if you stop at the bar for 2 hours 🙂 thermal, waterproof or windproof, this outer layer it is designed to protect you from the most annoying and often unpredictable elements 100% (wind, rain). To be kept in the back pocket of the jersey (if it is not too heavy, for more competitive riders) or to be placed in a backpack and taken out when necessary. If you ride at night and for your safety, opt for clothing with bright, reflective colors.
MANIA
The 2 extremities of the body (hands and feet), in some subjects, are very difficult to keep warm without sweating. The sensations felt are numbness and tingling. They are 2 very personal areas of the body: I know people who do cyclocross races in the snow without gloves and people who go out in thermals on a Sunday trip on a beautiful sunny winter day. Here we must be the ones to choose a warm garment that does not make us sweat: it is often a fine line between well-being and sweat. We don't exaggerate with the heaviness so as not to ruin the riding feeling: in MTB, the thinner the glove, the more sensitivity we have on the grips. The important thing is that the front part has a heavier membrane (being in contact with the wind) while the rear part is thinner for a better grip (the more technical models already have these features).
FEET
There are some ways to keep your feet warm during your MTB rides in winter: use winter shoes, in Gore Tex or other materials, or shoe covers or wear warm socks: merino wool socks (example) can help keep your feet warm. warm and dry feet while cycling (preferable to cotton).
I do not recommend shoe covers because you often walk on MTBs and they risk getting ruined/torn in a short time: there are MTB models that leave the bottom of the foot free, but honestly I would keep it as the last choice if you don't want to get a model of winter shoe.
The goal is to keep your foot warm without making it sweat! If you find yourself in that bad situation where you're cold but can't keep your foot warm without making it sweat, try working on layers, perhaps wearing two pairs of socks: a very thin pair in synthetic fabric, over which you'll wear heavier socks , so as to create a minimum of breathability between the 2 layers.
EXTRA FEET MAKEUP
If you really can't warm up those blessed feet, you can try replacing the insole of your shoe with a heavier model, given that the shoes on sale (usually) are sold with very breathable insoles. This is of course if you don't have a winter shoe model, which is already equipped with a windproof sole.
LEGS
The legs are perhaps the point least subject to the cold: they are always in constant movement and blood circulation is always excellent. Here we don't have much advice to give, other than choosing long or short trousers based on the temperature and your perception of heat. On this item of clothing, you can dare to be light, given that it is a very active part of the body (there are many long and breathable models on the market). TIP: under the long trousers, you can use a classic lycra trousers with seat pad and braces in order to have comfort and a light extra layer.

PROJECTED IMPACT
Protect the extremities (head, hands and feet): in the cold, blood drains from the extremities, which quickly become numb. AND the multilayer principle (for the upper body). And always pedal! We try to limit long stops only at the end of the tour... or at the refuge 🙂
