Air pressure changes with altitude.
As altitude increases, there is generally less air above you, so atmospheric pressure decreases.
FACTS
Weather Facts
Understand everyday weather through facts about clouds, pressure, wind, storms, and temperature.
Wind is driven by pressure differences.
Air tends to move from areas of higher pressure toward areas of lower pressure, with Earth's rotation and friction also affecting the flow.
Clouds form when moist air cools enough for condensation.
Water vapor can condense onto tiny particles in the atmosphere, forming droplets or ice crystals.
Thunder follows lightning because light travels faster than sound.
The flash reaches an observer before the sound arrives, even though they occur as part of the same event.
Humidity describes moisture in the air.
Relative humidity compares the amount of water vapor present with the amount the air could hold at a given temperature.
Warm air can hold more water vapor than cold air.
This helps explain why cooling moist air can lead to condensation.
Hurricanes need warm ocean water to develop and strengthen.
Warm water supplies energy to the storm system, although many atmospheric conditions also matter.
Snow can fall when surface temperatures are above freezing.
Snow may survive to the ground under some atmospheric conditions, so the surface temperature alone does not determine precipitation type.
Fog is a cloud near the ground.
Fog forms when air near the surface becomes saturated and water droplets or ice crystals form.
Weather forecasts are probabilistic.
Forecasts represent predictions based on observations and models, so uncertainty naturally increases for some situations and longer time horizons.
Why context matters
Interesting facts are easier to remember when you understand the process behind them. Use these short explanations as starting points for further reading, and compare related ideas across Qevanu's other categories.
Frequently Asked Questions
Are these facts meant to be memorized?
They can be used for quick learning, but understanding the explanation is more useful than memorizing isolated sentences.
Can a fact have exceptions?
Yes. Scientific and technical statements often depend on conditions. The explanations here use the ordinary context stated by each fact.