London's weather is very strange. It can rain several times a day; each time the rain may come suddenly after the sun is shining brightly. The air is damp and chill right through July. On one March afternoon on Hampton Heath last year it rained three times, there was one hail(冰雹) storm, and the sun shone brilliantly --all this within two hours' time. It is not unusual to see men and women rushing down the street on a sunny morning with umbrellas on their arms. No one knows what the next few moments will bring.