Visiting spain in august

Where in Spain? It's a large country with considerable climate variation.

In Andalucía the odds of "miserably hot" are very high. Wunderground.com will give you daily actual weather stats going back more years that you'll want to look at. I've linked to the monthly data for August 2017, during which the temperature hit 100 or higher on 18 days.

Madrid and surroundings may just be "too hot". Barcelona's temperature is likely to be a bit lower, but it was rather humid when I was there the first 10 days of August 2016, so it felt hotter than the temperature indicated--not pleasant, but bearable. (But I'm from Washington DC, which has miserable summers itself.)

The stretch of northern Spain between the Basque Country and Galicia is typically much cooler, and of course up high in the Pyrenees heat would not be an issue.

I’d add the regions of Murcia and Extremadura to the extremely hot list for August.

I haven't been to Murcia, but I certainly agree about Extremadura. It positively bakes. Other problem spots are Zaragoza and even the Cerdanya Valley in the north.

It will be like visiting Spain in June only warmer.