Why is Singapore So Hot? Exploring the Reasons Behind the Tropical Heat

Goh Jun Cheng

Singapore is known across the world as a country with a characteristically hot and humid tropical climate. Its location just 137km north of the equator results in plenty of sunshine and high temperatures year-round. But what exactly leads to the sweltering heat that visitors and locals alike experience in the city-state?

This article dives into the diverse reasons behind Singapore’s signature hot weather.

Proximity to the Equator

The primary factor behind Singapore’s persistent heat and humidity is its proximity to the equator. Singapore lies only 137km north of the equator at around latitude 1°17’N.

Being located so close to the Earth’s equatorial belt means the country experiences intense and prolonged exposure to direct overhead sunlight throughout the year. The sun’s rays shine almost perfectly perpendicular onto Singapore most days, concentrating solar heat energy.

Minimal Seasonal Variation

Singapore’s equatorial location also means it does not experience significant seasonal shifts in the sun’s trajectory and solar energy as countries further north or south do.

With no major axial tilt, the midday sun passes almost routinely overhead daily in Singapore. The sun follows a consistent arch minimally affected by seasonal changes.

Thus, heat and humidity maintain fairly constantly year-round rather than going through major summer-winter swings. Temperatures fluctuate by only a few degrees Celsius monthly in Singapore. The weather stays hot and tropical without respite.

Wind and Rain Patterns

Prevailing wind flow patterns further contribute to Singapore being an intensely hot and humid island.

Winds generally blow from cooler maritime directions like the south and southeast. As these winds pass over warm waters surrounding Singapore, they pick up moisture and heat up.

By the time winds reach land, they elevate temperatures and moisture levels. Still air leads to further heat buildup.

While bouts of rain and wind temporarily offer relief, sunshine soon restores steamy conditions after downpours.

Urban Heat Island Effect

Although naturally hot based on geography, Singapore suffers further warming known as the urban heat island effect.

Concentrated urban infrastructure like densely packed buildings, vehicles, machinery and crowded human activity generate substantial waste heat in cities. This anthropogenic heat output contributes on top of sunshine to push temperatures higher.

Built surfaces like asphalt also trap heat within an urban environment. Urban greenery has been increased to provide cooling. But city-centric warming remains an issue.

Trapped Humidity

Singapore’s stable, rain-fed humidity also makes the country feel hotter than the thermometer readings.

Water vapour is a greenhouse gas that prevents heat from adequately dissipating under normal gradients. It acts like a insulating blanket trapping thermal energy.

Since Singapore lies in the humid equatorial belt, this moisture-rich air makes the perceived temperature feel several degrees warmer than the dry measure.

The high humidity intensifies the sweltering sensation of Singapore’s climatic heat.

Influence of Surrounding Seas

The warm waters surrounding Singapore further exacerbate its inherently hot weather.

Singapore is an island nation enveloped by some of the warmest tropical seas in the world. Nearby waters include the South China Sea, Strait of Malacca and Java Sea.

These regional waters absorb massive solar energy being near the equator. Heat is transferred to Singapore via prevailing winds. Warm surrounding oceans act like a radiator continuously emitting thermal radiation to the country.

Maritime effects augment the hot, muggy environment of Singapore throughout the year without cold ocean currents for relief.


In summary, Singapore’s perfect equatorial location coupled with urban density, rainforest humidity and heated surrounding oceans combine into a muggy thermal mix that shapes its trademark sweltering climate.

The city has found ways to cool itself through greenery and architecture, but the fundamental tropical heat remains challenging to escape. Understanding the diverse reasons behind Singapore’s climate provides insight into adapting within its unique geography.

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