The Capital Weather Gang posted an article describing some of the weather effects that are likely to be seen if you are in or near the path of totality on Monday August 21. Temperatures are likely to drop from the lack of incoming sunlight and clouds may also change since the daytime heating will be reduced.  For a full description, you can read more at https://www.washingtonpost.com/amphtml/news/capital-weather-gang/wp/2017/08/14/temperatures-may-plunge-more-than-ten-degrees-during-total-solar-eclipse/.