that close, heavy, claustrophobic weather. What is it?

Fire

I love rain; Snow, hail, storms, even very sunny, clear, super-hot weather. The one state of weather I find horrible (impossible) is the heavy, "close" kind of weather than narrows my eyes and gives  me a headache. (Yes, it might be psychosomatic).  In snow I can dress up warm. In hot weather I can lie in front of a fan. "Close" weather cannot be mitigated.

Now, my question is this: What is it I'm responding to and bridling against?  I check "humidity" levels as reported on weather sites and my feeling has no correspondance with those stats. "Air pressure" neither.  The breeze doesn't change this state - it's not about wind speed). It's not a rural / urban pollution thing either. It's not a breathing thing, it's more to do with eyes/headache/like living under miles of water.

 I don't know the details of how, or more to the point, where these measurements are taken (altitude) - I would assume at ground level locally. But what people describe as "humid weather" in London or Kingston, Jamaica, according to the weather stats, is not.

It bugs me not to understand it and how much this weather affects me above all others. Your insights are welcome. Thanks

Fire

https://www.xcweather.co.uk/forecast/n87ly

pansyface

We would appear to have much higher humidity than you right now but “close” is not how I’d describe the weather.

There’s a wind blowing that would pull your washing off the line. The gusts feel much stronger than those given on the chart.

The sunshine is bright and glaring - not a blue sky, more like white.  It feels like it could rot your eyeballs in the same way that snow blindness does.

We don’t get “close” weather here. 😁

Uff

Fifty, 60 years ago when we had that weather and used to say it was close it was usually just before a huge storm that was brewing which cleared the close feeling after it had passed. Something to do with the high pressure I think. 
These days low pressure really gets me. It gives me a heavy feeling in my sinus and a headache behind my eyes that paracetamol hardly touches. When it's really bad I feel quite nauseous. 

Fire

@pansyface 40% humidity is pretty low.

Allotment Boy

I agree it's a combination of pressure and humidity. 

Fire

But the given air pressure is high and humdity low.

@raisingirl any thoughts on this?

Lyn

It’s been lovely here,  cool breezy and shady,  I’ve had a cardi on all day.
forecasts 10° for tonight and 18° tomorrow.

Posy

I believe humidity is part of it even though the figures look low. It's also that stillness when there's no air movement at all. I wish I were a scientist and could explain it all because I feel just like you do!

Astraeus

I can't say what causes your malaise but I, like @Uff, sometimes find myself affected by high pressure shortly before it breaks. I often took those headaches to be a harbinger of storms.

Busy-Lizzie

It was 35° in SW France today. Usually by evening it is cooler with a breeze but this evening is hot and still. Horrible. May be 40° by Sunday/Monday. Wish it would rain.