Sometime tiny frogs appear on the terrace of high buildings after rain. Do they come from sky (clouds)?

No, I think they come up from the ground, just not as fast and not taking the elevator or stairs the way people do. There are all sorts of cracks and spaces in a building that most people never think about. Next time you've got some time, look around on the base of your building, both inside and outside. If possible, get the building custodian to show you inside. Ask him this question. Many building custodians will be glad that you are taking an interest in the structure of their building, and they many be proud to show you what they know. Be polite and don't forget to thank her or him for their assistance.

The assumption about frogs and fish raining from the sky is that they were picked up by waterspouts - tornadoes over water - and deposited over dry land.

Kiss one and one of them might tell you!

MAYBE THAT'S WHAT ANGELS REALLY LOOK LIKE AB

lol. good thinking but wrong answer, i think that the humidity makes them feel great so they come out of their hidden places (most of them just got out of their eggs) sorry but: it aint rainning any frogs soon!!!! :)

nope

I guess it very possible that rain brings little frogs.

It is possible that the frogs were lifted into the clouds and then dispersed by the rain; or there may have been a tadpole farm on the terrace and the frogs were transformed to their juvenile state by the rain.

No, they probably live in some kind of crevice in the building and come out when it rains to absorb the moisture they need to live.