Are charcoal suits good for the summer or are they too dark? Same question would also apply to Navy coloured suits, I've always thought that maybe light grey and khaki coloured suits should be the only suit colours in summer.
It is usually too hot in the summer for me to want to absorb additional sunrays. If you want to wear suits in the summer, stick with the lighter colors: khaki, greys, lighter shades of navy. Characoal is too dark imo.