In fact because of the location near the equator the length of daylight, and hence daily insulation, also varies only slightly from day to day. There is an average of 12 h of daylight and 12 h of darkness each day through the year. One of the biggest influences on the diurnal cycle of temperature is the presence of clouds, which generally reduce the solar heating at the surface and the net incoming long wave radiation received at the surface during the night. The timing of the cloudiness will affect the shape of the temperature curve. Clouds also act as an “atmospheric blanket” that helps to regulate the temperature at Earth's surface. During the day, clouds reflect a portion of the solar energy that reaches Earth back into space. This prevents the planet from becoming too warm. Clouds make for smaller diurnal temperature ranges because, all else being equal, they make the daytime cooler and keep the nighttime warmer compared to clear-sky conditions. However, cloud top height is also important. Higher clouds also tend to be colder, so they emit less long wave radiation, so are better at keeping more of it in our atmosphere rather than emitting it out into space. Low clouds are warmer and emit more of this long wave infrared radiation. During the day, clouds can make the temperature on Earth cooler by blocking heat from the sun. At night, clouds can make Earth's temperature warmer by trapping heat that came from the sun. Observations have shown, however, that warmer temperatures seem to create less dense, low-level clouds instead. The evidence we have so far suggests that this effect occurs because, as temperature increases, the air near the surface becomes drier, causing the cloud base to rise and reducing the cloud layer thickness.

One of the biggest influences on the diurnal cycle of temperature is the presence of clouds, which generally reduce the solar heating at the surface and the net incoming long wave radiation received at the surface during the night. The timing of the cloudiness will affect the shape of the temperature curve. Clouds also act as an “atmospheric blanket” that helps to regulate the temperature at Earth's surface. During the day, clouds reflect a portion of the solar energy that reaches Earth back into space. This prevents the planet from becoming too warm. Clouds reflect solar incoming radiation and both water vapor and clouds efficiently warm the surface radioactively in the infrared and weaken the amplitude of the temperature diurnal variation produced by the solar incoming variation. Secondly, clouds also have an important effect on Earth's temperature. But it's a bit complicated: Clouds can both cool down and warm up the temperatures on Earth. Clouds can block light and heat from the Sun, making Earth's temperature cooler. You've probably noticed this kind of cool down on a cloudy day. At night, since there is no reflection, instead of cooling temperatures, clouds help to keep them warmer. This happens when clouds trap the heat and reemit it back towards the planet's surface. With clear skies, the heat can easily travel into space leading to cooler temperatures. The combination of nearly even hours of daylight and darkness, the even intensity of radiation through the year, and the high humidity associated with the climate, keeps the diurnal range of temperature very small. Because the sun rays fall vertically near the equator as the sun rays fall vertically in this zone, the difference between day and night temperatures is minimum.