Why is the temperature difference between day and night at the equator small?

The equatorial region has low latitude, and the average sun height is high at noon all the year round, so the temperature is high; In addition, it is tropical near the equator.

The sea area is large and rainy, resulting in a small temperature difference between day and night. And there are counterexamples, tropical deserts have different climates.

Because the surface desert is not conducive to the regulation of temperature, the temperature of sunlight is high during the day and low at night, resulting in a large temperature difference between day and night.