The problem you have is that if he gets wet /muddy during the day will you be able to get him dry enough to rug overnight ? Could you swop to a no fill during the day and then back into his proper rug overnight ? Our Dartmoor is stabled overnight and she still has her rug on during the day but she is quite old and the lady who looks after her for us thinks she 'feels the cold' , I'm not convinced !
I think it depends on what you're doing with him. The fact that you've not clipped a cob suggests you're not riding him at the moment - or not very hard when you do.
Therefore that takes away one of the main reason people rug at this time of year ie to keep them clean and dry for putting tack on and riding.
If you're not riding and you don't mind how wet and muddy he gets then you're right to check his warmth, weight etc. I would say that, although wer're in mid Feb, I don't think we over the worst yet. I think we'll get some more rain and overnight frosts. I'd keep a thin New Zealand type rug on him until the end of this month and then see how he's doing.
Mine are out 24/7 and I took their rugs off today as it was warm and sunny and I thought it'd be nice for them to feel the sun on their backs.They are unclipped and very woolly.If a frost is forecast,or heavy rain,I'll put them back on.
Ours could have had their rugs off a couple of times this week but the weather is so changeable, sunny one minute, cold rain and wind the next. If they get wet and muddy there is no chance of us getting them dry enough to put a rug back on them. Dhorse in particular hates to feel cold and will shiver pitifully despite being a big hairy cob, which is why we don't like to mess them about, if we start rugging then we see it through until the spring, and it is still only February!
Ours all have no-fill rugs but tbh we don't like them much so they rarely get used. Do you find they feel cold and a bit clammy underneath them?