The whole of human society operates on knowing the future weather. For example, farmers in India know when the monsoon rains will come next year and so they know when to plant the crops. Farmers in Indonesia know there are two monsoon rains each year, so next year they can have two harvests. This is based on their knowledge of the past, as the monsoons have always come at about the same time each year in living memory. But the need to predict goes deeper than this; it influences every part of our lives. Our houses, roads, railways, airports, offices, and so on are all designed for the local climate. For example, in England all the houses have central heating, as the outside temperature is usually below 20°C, but no air-conditioning, as temperatures rarely go beyond 26°C, while in Australia the opposite is true: most houses have air-conditioning but rarely central heating.