By formal, I usually think a jacket or smart-looking shirt... I like some of the light cotton and linen shirts and jackets from a brand called UNIQLO.
What are some formal clothes for summer?
Jackets seem more suitable as the cold has ended so multiple jackets like Jean jackets, some people find that shorts are also better since the temperature has greatly increased, some people might not suggest leather wear but why not leather? Almost always looks cool during the summer.
I tend to wear Jim Morrison style Nepal leather pants taken a custom Jean sit, perhaps styled leggings like tye dye too... not just plain black ones which just look mundane in my opinion.
As a suggestion, try to get a custom outfit from a seamstress. I am getting one myself after I selected this template to follow:
Oxford cloth button downs in white, light blue and light
grey will be necessary. Chinos/dress pants in light khaki; dark khaki, navy,
and a darker grey will come next.
Mostly cotton clothes are better for summer. The formal type of cotton dresses are lace dresses, Empire wear, knee length formal dresses, skirts etc are best formal wear for women in summer.