I wonder if your girl is related to my girl...
All winter she has to be blanketed, no exceptions. When it gets below 30*, it's time for her heavy weight. Above 30*, it's midweight weather. During the spring and summer, anytime it rains she has to have her rain sheet on, otherwise, like your girl, she'll pathetically shiver. The temperature doesn't matter, only the fact that it's raining.
THEN! Every sunny day in the fall/spring/summer, she has to wearing her flymask. She has Moon Blindness and UV rays really exacerbate her condition so horse "sunglasses" for her! Since she's also mostly blind, her flymask also has to be taken off at night so she can use what little eyesight she has to maneuver around the pasture. That also means that she needs that mask right back on very early in the morning.
Then, there's the whole blindness thing. It's not easy to be thinking about where your own feet are going AND where the feet of the horse you're dealing with are while you're walking together.
I should probably also get her a flysheet this summer since she appears to be super allergic to some kind of bug bite (she has a couple of giant welts where she's been bitten) which is another thing that would be taken off and put back on all the time.
Basically, for my part, I just watch the weather forecast and preemptively flymask/blanket/whatever her. That way I'm hardly ever somewhere half panicking because she's without something she needs and I'm too far away to just go take care of it.
I sure wish she could call and tell me what she needs!
That would be ideal. Even better, if she could put her blanket/flymask on herself!
The price we pay for love, I guess! :)