"Wow, Honolulu is hot!"
Translation:Hū ka wela o Honolulu!
I just commented on the "Wow, it's humid!" thread, which is translated as "Auē kēia ikiiki!" However, I notice that this sentence translation utilizes the more common structure "Hu ka wela!" Wouldn't you also be able to say "Hu ka ikiiki!" Or do we only say "Hu ka hot/humid/cold/etc" when we are describing a place such as Honolulu?
In many situations the meaning will be very similar, but the grammatical structure is completely different. "Ka wela o Honolulu" is just a noun phrase ("the heat of Honolulu"), but can be used in Hawaiian as an exclamation. "Wela 'o Honolulu," is more of a complete sentence with a verb and a subject ("Honolulu is hot"), but since the subject is a proper noun, it must be marked with 'o.
The article "ka" indicates that "wela" is acting as a noun here and not a verb. Notice that I said you use 'o when it marks "Honolulu" as the subject. In this sentence, "wela" is the actual noun and "Honolulu" is just a descriptor ("the heat of Honolulu") so it uses just o to connect them.
In general, us "ke" before words that begin with k, e, a, or o and use "ke" before most other words. Remember that ' is a letter of the alphabet so if the word starts with 'e, 'e, or 'o it probably gets "ka". There are plenty of exceptions, so sometimes you just have to memorize which article it gets. I've noticed that a lot of nouns borrowed from English use "ke" even though they don't start with one of the given letters.