The USA is a very big country. The weather is different in different places.

New York is a famous（著名的）city. It is hot in summer and there is a lot of snow in winter. In May and October, it’s not too hot or too cold. New England’s weather gets cool and the trees start to change colour in September.

In Los Angeles, California, the weather is nice all year. It’s nice and warm in December and you can swim in the sea.

In the northwest, it isn’t very cold, but there is a lot of rain, so people often need to use umbrellas. It is pleasant in August, but you need some warm clothes in the evening. In winter, it is dark（黑的）all day and very cold in Alaska.

It’s usually hot and sunny in the southeast.

Different weather makes people feel different. It influences health, intelligence (智力) and feelings.

In August, it is very hot and wet in the southern part of the United States. People there have heart trouble and other kinds of health problems during this month. In the Northeast and the Middle West, it is very hot at some times and very cold at other times. People in these states have more heart trouble after the weather changes in February or March.

The weather can also influence intelligence. For example, in a 1983 report by scientists, IQ of a group of students was very high when a very strong wind came, but after the strong wind, their IQ was 10% lower. The wind can help people have more intelligence. Very hot weather, on the other hand, can make it lower. Students in many schools of the United States often get worse on exams in the hot months of the year (July and August).

Weather also has a strong influence on people’s feelings. Winter may be a bad time for thin people. They usually feel cold during these months. They might feel unhappy during cold weather. But fat people may have a hard time in hot summer. At about 18℃, people become stronger.

Low air pressure may make people forgetful. People leave more bags on buses and in shops on low-pressure days. People feel best at a temperature of about 18℃.

Are you feeling sad, tired, forgetful, or unhappy today? It may be the weather’s problem.

Summer 2023 has beaten heat records worldwide. On July 6, the average worldwide temperature reached the highest on record.

Scientists are still trying to work out all the reasons for this summer’s historic heat. But one thing is certain: it has a lot to do with human-caused climate(气候) change.

Much of this summer’s heat is probably related to Earth’s oceans, experts say. Oceans worldwide have been warming for decades (十年), largely because of the greenhouse gases produced by humans. The warm oceans can’t take in as much heat from the atmosphere (大气层). This leaves more heat in the air, leading to warmer summer weather.

El Nino may also have helped turn up the heat this summer. El Nino happens naturally every several years. It warms the waters of the tropical (热带的) Pacific. But Earth’s new period of El Nino only began in June and won’t be at its strongest for months. So it’s too early to say how much El Nino has added to the hot weather this summer, researchers say.

Another possible reason for the high temperatures is the heat waves. Heat waves happen when powerful winds flow more slowly through Earth’s atmosphere. This can cause hot pockets of air to stay over the same places for days or weeks at a time.

One recent study showed that human-caused climate change is making heat waves more common and more serious. Researchers made computer models of the world with and without climate change. Then, they compared how often heat waves would happen in each case. The models showed that heat waves are now expected about once every ten years in Europe and North America, but they would be almost impossible without climate change.

It’s too early to work out the cost of all that unusual weather. But hundreds of deaths have been reported around the world. And the great need for air conditioning has heightened people’s worry about power shortages. Those problems will only become more serious as climate change creates more hot summers like this one.