Okay kiddo, imagine you have a thermometer, the thing that measures how hot or cold something is. Now let's say you check the temperature every day at the same time, like after you wake up in the morning. You would write down the temperature you see on the thermometer and keep doing that every day, right?
Now imagine if we did that for a really long time, like for many years or even decades. We could see how the temperature changes over time and keep track of the highest and lowest temperatures we've seen.
That's what a temperature record is! It's a long list of all the temperatures that have been recorded in a particular place over a long period of time. Scientists use this list to understand how the climate and weather patterns change over time.