BWh: B = Arid W = Desert h = Hot arid
Hot desert climates (BWh) are typically found under the subtropical ridge in the lower middle latitudes or the subtropics, often between 20° and 33° north and south latitudes. In these locations, stable descending air and high pressure aloft clear clouds and create hot, arid conditions with intense sunshine.
At the time of high sun (summer), scorching, desiccating heat prevails. Hot-month average temperatures are normally between 29 and 35 °C (84 and 95 °F), and midday readings of 43–46 °C (109–115 °F) are common. The world absolute heat records, over 50°C, are generally in the hot deserts, where the heat potential can be the highest on the planet. This includes the record of 56.7°C in Death Valley in the United States, which is currently considered the highest temperature recorded on Earth. Some deserts in the tropics consistently experience very high temperatures all year long, even during wintertime. These locations feature some of the highest annual average temperatures recorded on Earth, exceeding 30°C up to nearly 35°C in Dallol, Ethiopia. During colder periods of the year, night-time temperatures can drop to freezing or below due to the exceptional radiation loss under the clear skies. However, very rarely do temperatures drop far below freezing under the cold subtype.
Köppen–Geiger climate classification map for desert climates - source: wikicommons, authors: Beck, H.E., Zimmermann, N. E., McVicar, T. R., Vergopolan, N., Berg, A., & Wood, E. F., 2018
Hot desert climates are found across vast areas of North Africa (e.g. Luxor International Airport), Western Asia (e.g. Ha'il Regional Airport), northwestern parts of the Indian_Subcontinent (e.g. Karachi/Jinnah International Airport), interior Australia (e.g. Ayers Rock Connellan Airport), and smaller areas of the Southwestern United States (e.g. Las Vegas McCarren International). Hot deserts are present in every continent except Antarctica, with Almería in Southern Spain also having this climate.
Flight safety and planning considerations
High ambient temperatures can have a significant and limiting impact on aircraft and human performance, as well as causes significant maintenance issues. See the related articles on Hot Weather Operations and Hot and High Operations.