First impressions count at an interview. I would wear a light-weight summer suit, but certainly once you got the job a nice skirt and slacks as you describe would be fine. When you go for the interview you have no idea what their company policy is for dress code, so it is better to err on the side of caution with a suit.
As an older administrative professional I also suffer from hot flashes at work and it is always a challenge to find something to wear that will work. I wrote an article on my blog called Hot Flash: Working With Your Internal Temperature Turned Up.
Here is the link if you would like to read it:
All the best in your job search,