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What is weather?

Image of a night-time thunderstorm.
Night-time thunderstorm (1)

Many changes can occur within the air we breathe and the atmosphere as a whole. Winds can blow with great strength or be very gentle. Water may condense to form rain or snow. The temperature may be warm or cold. The changes that occur on short time scales, say over the course of a day, or several days, or from one season to the next, are what we call weather. We measure many different aspects of the weather, including such things as total rainfall per day, maximum and minimum wind speeds, high and low temperatures, or how much cloud cover there is.

For more information:

What is climate?

Image of a dried-up lake.
Dried-up lake

Climate encompasses all of the same phenomena as weather, but over much larger time scales, at least several years or more. In this case we would use units such as average annual temperature or rainfall per year, or average cloudiness, for instance. It is very important to understand that the term climate describes long term behavior in the atmosphere. A suggestion could be made that if one year is on average cooler than the previous year, then there can be no global warming. This is not good logic. One must consider several or many years to truly describe climate change.

(1) NOAA Photo Library, NOAA Central Library; OAR/ERL/National Severe Storms Laboratory (NSSL)


PBL Navigation

> PBL Scenario
> Layers of the Atmosphere
> What is a Cloud?
> Weather and Climate
> How Clouds Form, Saturation and Nucleation
> Clouds in the Lower Atmosphere
> Clouds in the Upper Atmosphere
> How Does Climate Affect the Atmosphere?
> Glossary

Teacher's Guide

I. AIM Mission Objectives
II. Key Questions for Students
III. Problem-Solving Model
IV. Materials and Procedures


A: Sample Student Activity Sheet
B: Assessment Rubric
C: National Science Education Standards

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The AIM mission is a part of
NASA's Sun-Earth Connection Education Forum.

Responsible Official: James M. Russell III

Web Curator: Emily M. W. Hill
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