I hope I have identified this tree correctly. This was the second time they were flowering this year though not as many flowers as the last time in February.
These trees were planted when the park was upgraded in 2007. More information about this tree can be found on the WildSingapore Factsheet website.
The mature leaves are oblong and elongated with a smooth surface, growing opposite each other.
I noticed the trees had many white flower buds on 17 May morning.
I am rather fortunate now that almost every weekday morning, I can walk around the park for about 15 minutes before I go to work. I hope I don't have to wait too long to see these beautiful and sweetly scented flowers again.