Changeable weather can lead to the "Rug Dilemma "
Here is a bit of advice taken from an extract written by Wendy Gill. Wendy has some great articles on her site Equine Freelance.
"Horses are very efficient at controlling their core body temperature when the environmental temperature is between around 5 to 25 oC, and in winter they can acclimatise to a wider range (e.g. down to -15oC). Unlike humans, normal digestion in the horse’s hindgut produces a large amount of heat and therefore owners will feel cold when their horses do not. Many owners feel their horse’s skin, to see if it is warm, but this is not accurate and can lead to over-rugging, which can have negative effects on the horse’s health".
If you have a weatherproof sheet to keep out the rain the horses will be happy. Standing on a warm day in warm rugs will be causing your horse stress. Horses find it very hard to cool down but have effective in built heaters.
I see loads of posts this time of year with people asking what rug? Try to put your mind in horse mode , Go for the waterproof lighter one.