On a cool day or on a cool night

On weekends, the preposition on has several typical uses:

1, indicating the orientation. On (and in contact with) the surface of something.

2。 Refers to the object, meaning "about".

3。 Indicate the time of morning, afternoon and afternoon before a specific date, or inform the weather.

When expressing the weather in English, we can use prepositions in and on, but the usage of these two prepositions is different. The preposition in mainly has the following ways: in+ "weather type" (good weather, bad weather, rain, storm, sun, snow, hurricane, tornado, tsunami, etc.). The preposition on is mainly used in the following ways: on+ "types of days" (sunny, rainy, cold, hot, snowy, etc.), so incooldays cannot be used.