prize1-1, Exercise 1: Weather and climate

Model answer:

Weather is what the atmosphere is doing at a place and time, such as today's rain or tomorrow's frost, and it changes by the hour. Climate is the pattern of weather over a long period, usually thirty years or more. A common mistake is to treat one cold week as proof that the climate is not warming, or one hot day as proof that it is; weather is the individual game and climate is the season's record.

Check the thirty-year convention against an official source.