10 most difficult me­te­o­rol­o­gy riddles

Mawsynram village in northeast India has the highest average annual total precipitation in the world (11,872 mm = 467.4 in). There, hot and moist air from the south of India approaches Himalayas. It rises up, cools and loses water.

Beaufort scale force 12 is the strength of the hurricane: huge waves, air filled with foam and splashes, sea completely white.

A psychrometer, or wet-and-dry-bulb thermometer, consists of two thermometers, one that is dry and one that is kept moist with distilled water on a sock or wick. The two thermometers are thus called the dry-bulb and the wet-bulb. At temperatures above the freezing point of water, evaporation of water from the wick lowers the temperature, so that the wet-bulb thermometer usually shows a lower temperature than that of the dry-bulb thermometer.

An anemometer is a device used for measuring the speed of wind, and is also a common weather station instrument. The term is derived from the Greek word anemos, which means wind, and is used to describe any wind speed measurement instrument used in meteorology.

The Morning Glory cloud is a roll cloud, or arcus cloud, that can be up to 1,000 km long, 1 to 2 km high and often only 100 to 200 metres above the ground. The southern part of the Gulf of Carpentaria in Northern Australia is the only known location where it can be predicted and observed on a more or less regular basis due to the configuration of land and sea in the area.

A long, typically low, horizontal, detached, tube-shaped cloud mass, often appearing to roll slowly about a horizontal axis. The roll cloud, volutus, is a soliton, not attached to other clouds and is an example of an undular bore.

Advection fog is formed by the passage of warm and moist air over a colder water surface. The air gets cooled and loses water. This kind of fog is common at sea whenever cold and warm ocean currents are in close proximity.

Humidity is the measure of the amount of moisture in the air. A psychrometer is an example of a hygrometer. A psychrometer uses two thermometers to measure relative humidity; one measures the dry-bulb temperature and the other measures the wet-bulb temperature.

Isohyet joins points where the amount of precipitation (rainfall, snow etc) is the same.

The Madden–Julian oscillation is a large-scale coupling between atmospheric circulation and tropical deep convection. Unlike a standing pattern like the El Niño Southern Oscillation, the Madden–Julian oscillation is a traveling pattern that propagates eastward, through the atmosphere above the warm parts of the Indian and Pacific oceans. This overall circulation pattern manifests itself most clearly as anomalous rainfall.