page_title: Sunshine duration
section_title: Geographic distribution
hierarchical_section_title: Sunshine duration / Geographic distribution
caption_attribution_description: English: Map of yearly sunshine hours in the world Italiano: Carta dell'eliofania annua nel mondo &#160;&#160; &lt; 1200 h &#160;&#160; 1200-1600 h &#160;&#160; 1600-2000 h &#160;&#160; 2000-2400 h &#160;&#160; 2400-3000 h &#160;&#160; 3000-3600 h &#160;&#160; 3600-4000 h &#160;&#160; &gt; 4000 h
context_page_description: Sunshine duration or sunshine hours is a climatological indicator, measuring duration of sunshine in given period for a given location on Earth, typically expressed as an averaged value over several years. It is a general indicator of cloudiness of a location, and thus differs from insolation, which measures the total energy delivered by sunlight over a given period.
  Sunshine duration is usually expressed in hours per year, or in hours per day. The first measure indicates the general sunniness of a location compared with other places, while the latter allows for comparison of sunshine in various seasons in the same location. Another often-used measure is percentage ratio of recorded bright sunshine duration and daylight duration in the observed period.
  An important use of sunshine duration data is to characterize the climate of sites, especially of health resorts. This also takes into account the psychological effect of strong solar light on human well-being. It is often used to promote tourist destinations.
context_section_description: Sunshine duration follows a general geographic pattern: subtropical latitudes (about 25° to 40° north/south) have the highest sunshine values, because these are the locations of the eastern sides of the subtropical high pressure systems, associated with the large-scale descent of air from the upper-level tropopause. Many of the world's driest climates are found adjacent to the eastern sides of the subtropical highs, which create stable atmospheric conditions, little convective overturning, and little moisture and cloud cover. Desert regions, with nearly constant high pressure aloft and rare condensation—like North Africa, the Southwestern United States, Western Australia, and the Middle East—are examples of hot, sunny, dry climates where sunshine duration values are very high.
  The two major areas with the highest sunshine duration, measured as annual average, are the central and the eastern Sahara Desert—covering vast, mainly desert countries such as Egypt, Sudan, Libya, Chad, and Niger—and the Southwestern United States (Arizona, California, Nevada). The city claiming the official title of the sunniest in the world is Yuma, Arizona, with over 4,000 hours (about 91% of daylight time) of bright sunshine annually, but many climatological books suggest there may be sunnier areas in North Africa. In the belt encompassing northern Chad and the Tibesti Mountains, northern Sudan, southern Libya, and Upper Egypt, annual sunshine duration is estimated at over 4,000 hours. There is also a smaller, isolated area of sunshine maximum in the heart of the western section of the Sahara Desert around the Eglab Massif and the Erg Chech, along the borders of Algeria, Mauritania, and Mali where the 4,000-hour mark is exceeded, too. Some places in the interior of the Arabian Peninsula receive 3,600–3,800 hours of bright sunshine annually. The largest sun-baked region in the world (over 3,000 hours of yearly sunshine) is North Africa. The sunniest month in the world is December in Eastern Antarctica, with almost 23 hours of bright sun daily.
  Conversely, higher latitudes (above 50° north/south) lying in stormy westerlies have much cloudier and more unstable and rainy weather, and often have the lowest values of sunshine duration annually. Temperate oceanic climates like those in northwestern Europe, the northwestern coast of Canada, and areas of New Zealand's South Island are examples of cool, cloudy, wet, humid climates where cloudless sunshine duration values are very low. The areas with the lowest sunshine duration annually lie mostly over the polar oceans, as well as parts of northern Europe, southern Alaska, northern Russia, and areas near the Sea of Okhotsk. The cloudiest place in the United States is Cold Bay, Alaska, with an average of 304 days of heavy overcast (covering over 3/4 of the sky). In addition to these polar oceanic climates, certain low-latitude basins enclosed by mountains, like the Sichuan and Taipei Basins, can have sunshine duration as low as 1,000 hours per year, as cool air consistently sinks to form fogs that winds cannot dissipate. Tórshavn in the Faroe Islands is among the cloudiest places in the world with yearly only 840 sunshine hours.
caption: Annual sunshine hours map of the world. Note that the data for Antarctica is accurate only for the coast. Parts of the interior receive more than 3600 hours of annual sunshine.[4]        < 1200 h   1200–1600 h   1600–2000 h   2000–2400 h     2400–3000 h   3000–3600 h   3600–4000 h   > 4000 h
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