Really, "during the day" would be most natural to me, unless this might mean "at daybreak."
Well, Siang means "Noonish, give or take a few hours", so "during the day" works, but not "at daybreak".
I agree! It seems this website is inconsistent as to what Siang and Sore actually mean. If Siang is 10am-2pm and Sore is 2pm-dark...then both could be considered “afternoon”. However, it is more natural to say “afternoon” for “sore.” And...what English word would be used to translate Siang if it is 10am? “Morning” makes more sense for pagi then siang. I think these are difficult to translate into English because our days are not divided in the same way. Morning is “before noon”. Then there is afternoon which is “after 12 o’clock”. Then evening, which is after dinner. And night which could also be used as after dinner but is used like “malam.”