Weather vs. Climate
"What's the weather?" is easily answered: "It's raining" or "It's hot." But to answer "What's the climate?" you need to know more. For example, what's the average temperature each month? How much does it usually rain or snow? Weather describes the conditions today, tomorrow or in the days to come. Climate is the average weather over years, decades or longer.
And Now, The Weather
Weather changes rapidly over days and weeks, so we rely on weather forecasters to tell us if we should pack an umbrella. But since climate is the average weather, a single weather event—a hot spell, for instance—does not say much about climate.
To learn about climate and climate change, we must look at the weather in the same place over longer periods of time: for the world as a whole, the 1990s were warmer than the 1960s.
Is It Weather? Or Climate?
It's so hot today!
That's weather, which can shift from day to day.
It rains a lot here.
That's climate, the average or usual weather.
It used to snow more when I was a kid.
When you compare current normal conditions to past decades, that's climate.
It seems like there have been more big rainstorms than usual this summer.
This statement is tricky: heavy rainstorms in one year are features of weather, but the "usual" number is a feature of climate. Although scientists expect more torrential rains as Earth warms, it is not possible to say if one year's storms are the result of climate change.