What is the difference between all the weather words: 気象{きしょう}, 天気{てんき} and 天候{てんこう}?


Dictionary (at least Jisho and WWWJDIC) defines them as:

  * 気象{きしょう} = weather, climate
  * 天気{てんき} = weather, the elements
  * 天候{てんこう} = weather

They all have quite similar definitions, so I don't quite understand the
difference. I would appreciate if someone could shed some light into this (in
English preferably), i.e. when to use each of these words.

Then there is the word 気候{きこう}, which I think means climate, and cannot be
used to describe the weather on a specific day. Is that correct?

Thank you in advance!




天気 (1-3 days): You'll hear 天気 used the most, as in 天気予報 _weather forecast_ or
天気はいいですか _Is the weather good today?_ You should almost always translate 天気 as
"weather" in English.

天候 (2-10 days): 天候 refers to the overall state of the atmosphere between a few
days to about 10 days. Its use isn't that common, however, in casual
conversation it shows up in the phrases 悪天候 "bad weather", referring the the
weather in the past week or two, or 天候に恵まれる "we've been blessed by the
weather."

気候 (climate) can be translated into English as weather or climate, depending
on the context, however, it's used to refer to timescales on the order of a
year. For example, カイロの気候はいいですか is the weather/climate in Cairo good? In this
case, you mean climate, but in English it's rare to ask "How's the climate
where your from?". Rather, "How's the weather where your from?" already
implies you mean weather on a large scale, season to season.

気象 (meteorological phenomena): For example, 気象学者=meteorologist but
天気予報官=weatherman. 気象 refers to weather/climate, as well, but in a bit more
quantitative context regarding changes in pressure and temperature, not simply
"hot" or "cold". An English equivalent would be, "I'm studying meteorology"
vs. "I'm studying weather." Studying meteorology means you're studying
weather, but if you merely said, "I'm studying the weather" it doesn't
necessarily carry with it the quantitative scientific connotation associated
with the word meteorology.




天気 (1-3 days): You'll hear 天気 used the most, as in 天気予報 _weather forecast_ or
天気はいいですか _Is the weather good today?_ You should almost always translate 天気 as
"weather" in English.

天候 (2-10 days): 天候 refers to the overall state of the atmosphere between a few
days to about 10 days. Its use isn't that common, however, in casual
conversation it shows up in the phrases 悪天候 "bad weather", referring the the
weather in the past week or two, or 天候に恵まれる "we've been blessed by the
weather."

気候 (climate) can be translated into English as weather or climate, depending
on the context, however, it's used to refer to timescales on the order of a
year. For example, カイロの気候はいいですか is the weather/climate in Cairo good? In this
case, you mean climate, but in English it's rare to ask "How's the climate
where your from?". Rather, "How's the weather where your from?" already
implies you mean weather on a large scale, season to season.

気象 (meteorological phenomena): For example, 気象学者=meteorologist but
天気予報官=weatherman. 気象 refers to weather/climate, as well, but in a bit more
quantitative context regarding changes in pressure and temperature, not simply
"hot" or "cold". An English equivalent would be, "I'm studying meteorology"
vs. "I'm studying weather." Studying meteorology means you're studying
weather, but if you merely said, "I'm studying the weather" it doesn't
necessarily carry with it the quantitative scientific connotation associated
with the word meteorology.

