We read in Genesis 8:22,

As long as the earth endures,
seedtime and harvest,
cold and heat,
summer and winter,
day and night
will never cease.

How do you explain this? Does God mean that during the flood, time ceased outside the Ark? It's not because it was very cloudy and dark that day and night ceased, is it?

Actually, I think all the text is saying is that now we are returning to the regular cycle of seasons, disrupted by the Flood. The poem applied to nature (and human agriculture) after the Flood only. Since this is poetry, we need to be careful not to overinterpret. That is, the way words and phrases combine to paint a picture is probably more important than the literal meaning of isolated lines.