What are the symptoms of the flu and how does it differ from a cold?

The flu symptoms come on very quickly (3-6 hours) vs. cold symptoms appear gradually. With the flu you typically see fever, aches (often severe), chills, tiredness (moderate to severe), dry unproductive cough, chest discomfort (often severe) and headache. With a cold, a fever is rare, you typically have aches (slight), mild tiredness, a hacking productive cough, sneezing, stuffy nose, sore throat, chest discomfort (mild to moderate).