Measured by average temperature over the whole year, the hottest cities in the world are Mecca in Saudi Arabia (31.2°C), Assab in Eritrea (30.5°C) and Bosaso in Somalia (30.0°C), according to Wikipedia's List of cities by average temperature (checked October 2026), which compiles national climate normals. Mecca's figure is from the World Meteorological Organization's 1991–2020 normals. Measured by the hottest month instead, the leaders change to Basra, Kuwait City and Ahvaz around the head of the Persian Gulf, where July averages close to 39°C. And the highest single reading ever accepted, 56.7°C, was taken in 1913 at Furnace Creek in Death Valley, which is not a city at all.
Three yardsticks: annual mean, summer peak and the record book
Every list of hot cities picks one of three measures, often without saying so. The first is the annual mean: the average of daily highs and lows across all twelve months, usually over a 30-year reference period. It rewards places that are hot all the time, including at night and in January. The second is the summer peak: the mean temperature or mean daily high of the hottest month, which rewards places with brutal summers even if their winters are mild. The third is the record high, a single afternoon, which says more about one heatwave and one thermometer than about everyday life.
This article ranks by the first measure, because it describes the climate people live in all year, and then shows how the order changes under the other two. One caution: the list mixes reference periods. Mecca uses 1991–2020 WMO normals, while Assab and Lodwar use 1961–1990, and several stations, including Abéché and Aden, use tables from Germany's weather service, the Deutscher Wetterdienst. A few tenths of a degree separate many cities, so small differences are within the noise.
Rival sources show how much that noise can move. Bangkok averages 28.6°C in the list but 28.9°C in the 1991–2020 table on its own Wikipedia page. Maracaibo drops from 28.7°C to 28.3°C when its 1991–2020 normals are used. Bosaso's hottest month is August in the list but July in its own article's table, at the same 36.1°C. The list also contains plain errors: its Marrakesh row gives 15.8°C for March and 36.3°C for November, so we leave that row out. The top four, all above 29.8°C, are stable whichever table you use, and Djibouti's 29.9°C is identical in both.
The annual-mean ranking, Mecca to Niamey
| Rank | City | Country | Annual mean | Hottest month mean |
|---|---|---|---|---|
| 1 | Mecca | Saudi Arabia | 31.2°C | 36.2°C (Jun–Jul) |
| 2 | Assab | Eritrea | 30.5°C | 35.0°C (Jul) |
| 3 | Bosaso | Somalia | 30.0°C | 36.1°C (Aug) |
| 4 | Djibouti City | Djibouti | 29.9°C | 36.4°C (Jul) |
| 5 | Valledupar | Colombia | 29.8°C | 30.5°C (Feb) |
| 6 | Ségou | Mali | 29.6°C | 34.1°C (May) |
| 7 | Abéché | Chad | 29.4°C | 33.3°C (Apr) |
| 8= | Garissa | Kenya | 29.3°C | 31.4°C (Mar) |
| 8= | Lodwar | Kenya | 29.3°C | 30.1°C (Mar, Oct) |
| 8= | Niamey | Niger | 29.3°C | 34.0°C (May) |
Aden in Yemen misses the ten by two tenths of a degree at 29.1°C, followed by Timbuktu in Mali and Sokoto in Nigeria at 28.9°C. Maracaibo in Venezuela sits at 28.7°C, and Bangkok and Ouahigouya in Burkina Faso at 28.6°C. No Gulf city comes close: Kuwait City averages 25.7°C over the year in the same list, Ahvaz 25.4°C and Riyadh 26.2°C, despite their fearsome summers.
Why Mecca comes first: warm winters in the Hejaz
Mecca sits 277 m above sea level in a narrow valley of the Hejaz mountains, about 70 km inland from Jeddah and the Red Sea, and had a metropolitan population of about 2.4 million in 2022. Its climate is hot desert (Köppen BWh). Summer afternoons regularly pass 40°C, with mean daily highs of about 43 to 44°C in June and July, but the key to its first place is the winter. In January the mean is still 24.3°C, with afternoons around 31°C and nights near 19°C. Kuwait City, by comparison, averages 12.5°C in January. A city that never really cools down beats one that bakes for four months and then turns mild.
The heat matters most during the Hajj, when pilgrims more than triple the city's population. The pilgrimage follows the lunar Islamic calendar, which is about eleven days shorter than the Gregorian year, so it drifts through the seasons; in 2024 it fell in mid-June. Between 14 and 19 June 2024, at least 1,301 pilgrims died from extreme heat as temperatures passed 50°C, and the highest reading reported at the Grand Mosque was 51.8°C.
Red Sea and Gulf of Aden ports: Assab, Bosaso, Djibouti and Aden
Three of the top four are low-lying ports on the southern Red Sea and the Gulf of Aden, and a fourth, Aden, comes eleventh. Assab, on Eritrea's Red Sea coast and founded as a port in 1882, averages 30.5°C, with July highs of 41.2°C and a record of 49.0°C. Bosaso, the main port of Puntland on Somalia's Gulf of Aden coast, averages 30.0°C and peaks in July or August (the list and the city's own table disagree on which), when the mean reaches 36.1°C. It is the commercial centre of Puntland and trades by sea with the Arabian Peninsula, and its station record stands at 45.3°C.
Djibouti City, home to about 780,000 people, or 73 percent of its country's population, averages 29.9°C in the Hong Kong Observatory's 1991–2020 figures. July is the worst month, with a mean of 36.4°C and mean afternoon highs of 42.1°C, and the station's record is 45.9°C. Across the Gulf of Aden, the Yemeni port of Aden, about 170 km east of the Bab al-Mandab strait and home to about 863,000 people in 2017, averages 29.1°C, about two degrees below Mecca. None of these places has a cool season: their coldest months still average about 25 to 26°C.
Sahel, northern Kenya and Colombia: Ségou, Abéché, Niamey, Garissa, Lodwar and Valledupar
The other entries reach the top ten in different ways. Abéché, capital of Chad's Ouaddaï Region, and Niamey, the capital of Niger on the banks of the Niger River, are Sahel cities whose hottest months are April and May, when monthly means reach 33 to 34°C. Ségou in Mali, 235 km northeast of Bamako on the right bank of the Niger, follows the same calendar: it averages 29.6°C and peaks at 34.1°C in May. The rainy months that follow are a few degrees cooler, which keeps the annual means of all three just under 30°C.
Lodwar, the capital of Kenya's Turkana County and home to 82,970 people in the 2019 census, shows the opposite pattern. Its monthly means barely move, from 28.4°C to 30.1°C, because it lies close to the Equator in the hot, dry lowlands west of Lake Turkana. Garissa, capital of Garissa County on the Tana River in eastern Kenya, ties with it at 29.3°C; it has a hot arid (BWh) climate despite about 375 mm of rain a year, and its warmest month, March, averages 31.4°C in the list's 1961–1990 figures. Valledupar, capital of Colombia's Cesar Department, works the same way: its months sit between 28.8 and 30.5°C. Maracaibo in Venezuela, just outside the ten, ranges only from 27.7 to 29.6°C. None of these places has a single month as hot as a Gulf summer, but none has a cool one either. For the same contrast at country scale, see our list of the hottest countries in the world.
The summer-peak contest: Basra, Kuwait City and Ahvaz
Switch to the hottest month and the ranking moves to the head of the Persian Gulf. In the climate tables of their own Wikipedia articles, Basra in Iraq averages 38.9°C in July, Kuwait City 38.7°C and Ahvaz in Iran 38.6°C, all hotter than Mecca's peak of 36.2°C. Their mean daily highs reach about 46 to 47°C in July and August. Basra stands on the Shatt al-Arab, the joined Tigris and Euphrates, and Ahvaz on the Karun River, both on the flat lowland around the head of the Gulf.
The same cities fall out of the annual ranking because their winters are cool: Kuwait City and Ahvaz both average about 12 to 14°C in January, depending on the table. So the honest answer to which city is hottest depends on the question. For a place that is hot every day of the year, it is Mecca or the Red Sea ports; for the hottest summer a large city endures, it is Basra, Kuwait City and Ahvaz.
Records and humid heat: Death Valley, Mitribah and Jacobabad
The record book belongs to small places. The WMO's official world record is 56.7°C, measured at Furnace Creek Ranch in Death Valley, California, on 10 July 1913. A reading of 57.8°C at ʽAziziya in Libya from 1922 held the title for about 90 years before being decertified in 2012, and some meteorologists have since questioned the 1913 reading too. If it fell, the record would be a three-way tie at 54.0°C between Death Valley (2013), Mitribah in Kuwait (21 July 2016) and Tirat in Mandatory Palestine (1942). Satellite measurements of ground temperature go much higher: 70.7°C in Iran's Lut Desert in 2005. The highest annual average for an inhabited place, 35°C between 1960 and 1966, belongs to Dallol in Ethiopia's Afar Depression, now described as a ghost town. Our page on the hottest temperatures ever recorded on Earth goes through these readings one by one.
A fourth measure, humid heat, may matter most for health. When the wet-bulb temperature, which combines heat and humidity, stays above 35°C, sweat can no longer cool the body, and the heat is likely to be fatal even to fit people resting in the shade. Jacobabad in Pakistan's Sindh province, where summer mean temperatures reach about 37°C, has passed that 35°C wet-bulb threshold several times. The city, named after the East India Company officer John Jacob (1812–1858), has been cited as one of the places most vulnerable to global warming, where the gap between 1.5°C and 2°C of warming could decide whether summers stay survivable. On the Gulf coast, Dhahran in Saudi Arabia recorded the highest heat index ever measured, 81°C, on 8 July 2003, when an air temperature of 42°C met a dew point of 35°C. It does not appear in any of the top tens above, but its combination of heat and humidity is among the most dangerous on Earth.