Atmosphere

Earth's rotation

The Coriolis effect is caused by Earth's rotation on its axis. As Earth rotates, moving air appears to curve - to the right in the northern hemisphere and to the left in the southern hemisphere. This effect is zero at the equator and maximum at the poles. It explains why winds don't blow straight from high to low pressure areas but follow curved paths instead.

Winds blowing from east to west

Trade winds are easterly winds that blow from east to west in the tropical regions. They are called Northeast trades in the northern hemisphere and Southeast trades in the southern hemisphere. These winds were historically important for sailing ships engaged in trade, hence the name 'trade winds'. They blow consistently throughout the year in the tropical belt.

Weather is short-term, climate is long-term average

Weather describes atmospheric conditions over a short period (usually up to 10 days) and can change daily or even within a day. Climate describes the average atmospheric conditions over a long period (decades) for a specific area. For example, saying 'it's raining today' refers to weather, while saying 'this region has a monsoon climate' refers to the long-term pattern.

Ratio of actual water vapour to maximum possible water vapour

Relative humidity is the ratio between the actual amount of water vapour present in the air and the maximum amount of water vapour the air can hold at that temperature and pressure. It's expressed as a percentage. For example, if air at 20°C can hold 80 gms of water vapour but actually contains only 40 gms, the relative humidity is 50%. When it reaches 100%, the air is saturated.