Climate versus weather

In the most succinct words, weather is the combination of events in the atmosphere and climate is the overall accumulated weather in a certain location.The exact boundaries of what is climate and what weather is are not well defined and depend on the application. For example, in some senses an individual El Niño event could be considered climate; in others, as weather.

When the original conception of climate as a long-term average came to be considered, perhaps towards the end of the 19th century, the idea of climate change was not current, and a 30 year average seemed reasonable. Given the current availability of data on long-term trends in the temperature record, it is harder to give a definition of climate to suit all purposes: over a 30 year period, averages may shift; over a shorter period, the statistics are less stable.