Solar weather is branch of meteorology, which studies behavior of sun and what type of predictions can be done. Solar weather research includes for instance doing simulations of possible behavior of sun. Uses are for instance giving warnings to satellites about possible solar storms.
Due to enormous size and mass of sun and complicated feedback systems solar weather predictions aren’t as good as normal – earth - weather predictions. (Exceptions with sun spots)
Solar weather is closely related to space weather and often included in same category.
References
Solar weather Wikipedia(Text) CC BY-SA