….on very cold days when, over a merino/synthetic base-layer, under a windproof shell. Boil in the bag?

Fleece comes in all sort of weights/thicknesses. It’s handy when it’s wet as it will act as a bit of a “reservoir” before letting sweat pass through your windproof layer. I find it a bit much for strenuous exercise though.

I’m thinking of a “mid” weight sweater type of fleece, polartec.

For all sorts of activities, fleece is still king in my wardrobe.

I have thin layers for winter cycling, mid weight for walking and day to day. Double up on a cold day.

I fund it breathes better and feels nicer than most synthetic full and down jackets, and is more robust long term.

The only downside is lack of wind proofing, but thin pertex or waterproof sorts that.

I even have a pair of old ME ultra fleece salopettes that are just lovely canoeing or in camp…

The combination you describe is exactly what I have always worn in the winter, and I find it works perfectly. I like to be warm, though, so it may not suit everyone.

The shell I wear when road riding lets me breathe well, but even I will admit that the RaceFace shell I wear over the fleece when mountain biking, because it doesn’t breathe at all, gets very warm indeed.

They’re very breathable (which is why they’re useless without a shell over the top in the wind)

They often come in 100, 200 and 300 weight, but there are other options too. A 100wt fleece is still pretty warm though

I often do the two or three base layers thing is well, instead of a fleece layer.

Personally I’d probably find even a Pertex/100 weight fleece combo far too much for riding. It’s the kind of thing that I’d usually wear hillwalking, where it’s much less strenuous.
On the bike I rarely go above base layer + windproof, maybe an extra (technical) T shirt over the base layer if it’s really cold.

Everyone’s different though, and where you live “really cold” might mean something different, so YMMV. I regularly see people riding around in kit that would see me melting into a puddle!

Its a good choice for a mid layer and can be surprisingly warm according to the weight.

For my commuting I have a selection to combine with an activeshell jacket – 100wt gillet, 200wt gillet, 100wt with sleeves, and 200wt with sleeves, and then a primaloft for when it is colder.

But if I was wearing a lifa and not a work shirt I probably wouldn’t need the primaloft.

Plus a goretex proshell instead of the activeshell for even more warmth…

If its wet I ditch the vest for fleece, being fluffier it’s nicer damp. Better still is pile. Depends how hot you get. And how sweaty. It has to be heavy rain before I get wetter from the outside than the inside.

When it gets cold I dump the base layer and just use a power stretch fleece next to the skin, I find it wicks much better and keeps me much more comfortable.

On very cold days, I’ll wear an old Karrimor fleece ( 100 I guess) gilet under a shell , over a long sleeve jersey.

For riding in the cold I have one of these 100wt gilets (actually slightly different side panels to mine) which is enough I reckon, under an event jacket and on top of the ever reliable lifa:

http://www.tog24.com/mens/gilets/mens-fleece-gilets/axis-mens-fleece-gilet-black.html

And can always do the zip right up if cold which is surprising effective, having the collar around your neck.

It all depends on how warm you get, and how cold it is, and the weight of fleece you’re wearing, how tired you tired you are and how much you’ve eaten and when can affect how warm you feel too.

That said, a thinner weight fleece can be just the thing for me when it’s cold enough for there to be snow and I’m not riding ‘full burn’, but more pottering along at the kind of pace where I could just about chat, and might have a Howies Waffle mid layer and a merino base layer underneath, with a wind/water proof on top. Through unzipping the zips when too hot, the lot can stay on and be all zipped up if it gets colder or I stop, so it can save fiddling with my bag, it has to be towards the ‘colder end of cold’ though.

A thicker weight gillet or body warmer can be just the thing for adding some core warmth without getting too hot, I bought a Regatta one for five pounds in CCC in Sheffield before it became Go Outdoors, and it’s one of my better impulse buys.

It’s probably a good idea to take a back up layer of warmth if it’s snow-cold.

Charity shops can be a cost effective way of buying fleeces to experiment with.

I’d die of heat stroke if I wore a fleece as a mid layer, whatever weight it was.

Last year at BPW, -5 at the top with a good Welsh wind, I had a thermal base layer and an Endura shell jacket on. The exposed skin felt raw in the wind, but once riding I was a puddle inside the jacket. Steaming by the time I got to the uplift bus.

For walking a fleece mid layer is perfect, riding I get too hot.

I’ve got two light layering fleeces (one Berghaus, one North Face) and I wear one between a merino base layer and Goretex shell on really cold days. Perfect and toasty and not too sweaty.

I have some fleece base layers. They are for sailing originally (Musto brand) but I also use them for skiing if it’s cold (eg January). I find them too hot for biking unless it’s really really cold. I don’t have a problem with them being damp / wet.

I have a set of endura winter bib tights which have a fleece lining

My feeling is merino plus fleece plus windproof would be fine for super cold conditions but otherwise too hot