Astrological transits are a part of what is usually called predictive astrology, the claim of astrology to predict or forecast future trends and developments. Most astrologers nowadays regard the term 'prediction' as something of a misnomer, as modern astrology does not claim to directly predict future events as such. Instead it is claimed that an astrological pattern with regard to the future can correspond with any one of a variety of possibilities. What is in fact foretold is the trend of circumstances and the nature of the individual's reaction to the situation
Mercury spends about a week in each natal house. During that time it affects your mental outlook, communications with others, and urges to take trips. When Mercury is in retrograde motion during its transit it may introduce delays in the affairs under its influence.