Once you’ve decided on what material you want then there are a number of choices in regard to construction.

It’s not as hard as it sounds, really. Basically, the choice is between long-sleeved, short-sleeved or sleeveless. Long sleeved is, barring any unseasonable weather, the base layer of choice for late autumn, winter and early spring. You can, of course, achieve pretty much the same effect with a short sleeved base layer and arm warmers under your jacket but the principle is the same: arms need more protection when the weather drops.

Arms – and especially cyclists’ arms – are lean and not hugely involved in the process of riding. Sure, you might move about a bit out of the saddle, and use your arms a bit more when you’re really going for it or sprinting but on a long ride the chances are that your arms will spend a lot of time pretty much still. That means they’re very susceptible to getting cold and a good quality long-sleeved base layer is an important bit of kit. If you really want to add warmth, you can get base layers with wind stopping fabric built in to add yet another level of protection against the elements. It’s only really an effective option for deep winter, though, as the windproof fabric often affects the breathability of the base layer.

Short-sleeved base layers are popular because they’re wonderfully versatile. Great for layering in winter and keeping dry/heat regulation in summer, a quality short-sleeved base layer can be one of the most valuable bits of kit in your wardrobe. As with any base layer, they need to be close-fitting, as they have to fit under a jersey that’s already made to be tight, and, more importantly, if they don’t sit next to your skin the wicking properties of the fabric will be lessened.

Sleeveless base layers are almost exclusively for summer. Although you can definitely use them as the bottom of multiple layers when the weather’s really cold, they’re super in the summer because 1) in summer the objective is normally to stay cool and 2) you never have that irritating game of trying to make the sleeves comfortable under your jersey. It’s for that reason that the vast majority of sleeveless base layers are synthetic. High wicking and quick drying properties are almost certainly the two most important qualities in a short sleeve base layer and if yours is good enough, you’ll definitely notice an increase in comfort.

Many summer base layers have a open mesh construction which keeps the weight extremely low and improves breathability. Conversely, some winter base layers also use mesh to great effect, including this number from Norwegian firm Bryjne. The thinking is that the mesh structure keeps air close to the body, while also allowing the skin to breathe and reducing the moisture trapped in the base layer itself.

Finally, let’s consider any other features you may find on a base layer.