We use during to talk about something that happens at a certain point within a period of time.
I met Charles during my stay in France. (It happened at one point within the period of time indicated by the phrase ‘my stay in France’.)
During can also be used to talk about an action or event that continues throughout a whole period of time.
I was in France during May. (= During the whole of May.)
The weather is hot during summer. (= During the whole of summer.)
The hotels were all fully booked during the summer season.
During and throughout
Throughout can be used instead of during when the reference is to a whole period of time.
Prices continued to rise throughout the 1990s. OR Prices continued to rise during the 1990s.
He was in Iraq throughout the war. (= He was in France during the war.)
During and in
In is sometimes used as an alternative to during to talk about actions or situations that happen within a period of time.
During the four years that I worked for them, I received a raise only once. OR In the four years that I worked for them I received a raise only once.
During and over
Sometimes over is used instead of during to describe a specified period of time.
I don’t intend to do much work over the summer. OR I don’t intend to do much work during summer.
Weather conditions have been steadily deteriorating over the last few hours, so a rescue seems nearly impossible.