1. Weather and Climate
Weather is the short term (day to day) conditions of the atmosphere.
Temperature
Precipitation
Humidity
Cloud cover
Wind
Air pressure

2. Climate Involves the key weather variables
Temperature
Moisture
Air pressure
But does so in terms of patterns over the course of decades.

3. Earth – Sun relationship
The Earth is attracted to the sun as a result of the gravitational pull of the sun.
The earth revolves around the sun once every year. ( days)
The Earth is tilted at an angle of 23.5 degrees throughout its orbit.
The Earth rotates on its own axis once each 24hrs.

4. Equinox
Because of the earth’s tilt there are only 2 times during the year when the sun shines equally on both the Northern and Southern Hemispheres: late March (20-23rd)
late September (20-23rd)
These times of the year are called equinoxes

5. Solstices
The times of the year when either the Northern or Southern Hemispheres receive the most sunlight are called solstices.
These occur during/around June 21(longest day of the year in NH) and December 22 (shortest day of the year in the NH)
Observe seasonal changes in the amount of sunlight reaching locations on Earth.
Explore a model of Earth's yearly revolution around the sun.
Climate Controls: Latitude

6. Solar Radiation

7. Solar Radiation

8. Cloud Cover and Temperature
During the day, the earth is heated by the sun. If skies are clear, more heat reaches the earth's surface (as in the diagram below). This leads to warmer temperatures.

9. Cloud Cover and Temperature
However, if skies are cloudy, some of the sun's rays are reflected off the cloud droplets back into space. Therefore, less of the sun's energy is able to reach the earth's surface, which causes the earth to heat up more slowly. This leads to cooler temperatures.

10. Cloud Cover and Temperature
At night cloud cover has the opposite effect. If skies are clear, heat emitted from the earth's surface freely escapes into space, resulting in colder temperatures.

11. Cloud Cover and Temperature
However, if clouds are present, some of the heat emitted from the earth's surface is trapped by the clouds and reemitted back towards the earth. As a result, temperatures decrease more slowly than if the skies were clear.