2 of my colleagues are sick and off from work with same symptoms today. Coughing, running nose, sore throat, headache & exhaustion. Coincidentally, they are not alone. There is a big spike in such cases during the summer to winter transition.
The problem is referred to as common cold or viral flu in general. The influenza virus which is responsible for this, is conducive to cold and dry weather. It is able to survive for longer and thus spreads quickly. Moreover, it can multiply / replicate faster as well.