Help with getting a smooth coat of paint in humid/cold weather

[Power Elephant]

This summer I got an airbrush for painting miniatures. Even though it was the cheapest thing I could get, I was still happy with it. But now, with rainy weather, no matter what I do paint turns into drops instead of a layer when it reaches the model. I've tried thinning the pain and adding more but neither helped. Then I figured that the problem is moisture since it's now fall and it rains all the time. I tried spraying at different distances, pressures. I tried to paint in sunnier weather, but the problem remained (although the drops were smaller this time). Finally I tried painting indoors but that didn't help either.
Is there any way for me to airbrush in humid and/or cold weather?

 

[Vladimir]

Are your surfaces for painting sanded (sandpaper or scotchbrite, etc) ?

 

[Power Elephant]

No, they aren't.

 

[Mr.Micron]

Well this is where an introduction would come in handy http://www.airbrushforum.org/introductions/
But being this is your first post I will try to offer help with the lack of detail I have .
First where is the area located you are painting in .. .Outside in the rain, in a unheated garage , in a unheated basement ?
What is the paints you are using ,,, IE Wicked, Golden, Model master ?
What compressor do you have ? A tankless one or a regular compressor with regulator that you can adjust the pressure.

I am trying to understand what you are saying. Right now it sound more like the paint is beading up on the surface of what you are trying to paint.
If so that is all prep work. That means there is some type of oil residue on the surface not allowing the paint to stick. That really does not have a lot to do with the weather unless you are trying to paint out in it.
See the better information you can give us and the more you can give us the better the answer .

 

[Power Elephant]

I tried painting outside after the rain stopped, in an unheated garage and in a heated apartment (although the room was a bit chilly). I'm using acrylic paints by MiG. I have a tankless compressor.

 

[Mr.Micron]

Do you have a Pistol grip water trap on your airbrush? The trouble with Tankless compressor is they build heat which add moisture to the air being made.
The water trap on them sometime fails allowing too much moisture into the air line which ends up in your airbrush.

If you could post a picture of how the paint is reacting to the surface that would help a lot .

 

[Ronald art]

I agree with Herb on this your main problem is your compressor , I am not familiar with the paint you use but it is acrylic so it will react to any moisture in the air or in the paint and a tank less compressor will like Herb mentioned add moisture to the air you use to spray.
most acrylic paints will also react to warm or cold contitions but not that extreme. In warm conditions it will dry faster and in cold slower

 

[Power Elephant]

I hope you can see the paint. I do have a pistol grip water trap.

 

[Mr.Micron]

It looks more of a case of not getting all the molding release agent off prior to applying paint. With enamel or urethane The reducer acts like a wax and grease remover. But they can cause the plastic to melt.
Try wiping in down with alcohol then repaint .

 

[Power Elephant]

I'll try that. Thank you so much for the help.