"I am washing the bucket this morning."
Translation:Ninaosha ndoo leo asubuhi.
Apparently Kufua is only supposed to be used for clothing, where Kuosha is used whenever you clean something with soap and water (which can include clothes).
Someone may be able to provide more clarification on this, but IMO it seems that Kuosha is always the safer choice to use.
Just because English says "this morning" doesn't mean other languages do it the same way. In German, for example, you say heute Morgen, "today morning" exactly the same as leo asubuhi in Swahili.
Notice also that we don't say "this night" in English but instead "tonight".