"Жаль, что сейчас идет дождь" - I wish it weren't raining. "Жаль, что я задержал их так надолго." - I wish I hadn't kept them waiting for so long. "Жаль, что..." - I wish, а дальше предложение либо в Сonditional Type 2 (The situation corresponds to the present or to the future) or Conditional Type 3 (the situation corresponds to the past)

Tiulpan, It's a pity... I wish... These are both ok. A more common expression would be-- Too bad it's raining now. Too bad I held them up so long.

жаль что сейчас идет дождь = It is a pity that now it is raining жаль, что я их задержал так надолго=It is a pity that I have detained them for a long time

Alexandre, yes one is the best, it's difficult to describe this phrase "Es una lástima que .." in English?

“Pity” is a good possibility for this, I guess.