That's a very good question, and as you might assume, has a complicated answer: It depends.
Mostly, it depends on what band you're listening to.
I'll give you some example from where I live, here in the midwest USA. Maybe someone can fill in the blanks for where you are.
19 meters and up - open to Europe in the mornings, South America in the afternoon, Asia in the evening. My best band to hear Voice of Korea (north) in the evenings.
25 meters - similar, but afternoons are South America and Africa and deep Asia. Early afternoon is a great time to look for All India Radio for example.
31 meters - DX does a flip flop here, mornings are Asia/Pacific, evenings are Europe, middle of the night South America. In addition, during sunset Asia comes through via greyline. Radio Australia just screams in here until well after dawn, until 9am or later usually.
41 meters - Same as 31 meters but greyline is really pronounced and the band may be filled with Chinese stations simply BOOMING in. After they fade, Europe dominates.
60 meters and down - Africa in the evenings, Pacific in the mornings. Best band for Africans until their sunrise, then it's South and Central America until near dawn when the Pacific Islands can be heard on a good day.
Hope that gives you an idea. Following the ham DXers might help.
Here's a page showing a map of what DX the hams are working:
QSO/SWL real time maps - EU - 50