Non Thais know the tree as the Golden Shower Tree. Its Latin name is Cassia fistula. The formal Thai name is “Rajapruek” which seems to be a popular name for Thai restaurants judging by the results of a Google search but in everyday conversation it is called Koon.
It blooms in March and April with extensive flowering. So much so that sometimes no leaves can be seen at all. It is more common up-country but not too difficult to find in the parks and along the roads in Bangkok. These photos I took in Queen Sirikit Park, which adjoins the larger Railway Park, which is a reasonable cycling distance from home. A stunning tree in more ways than one. Its seeds are poisonous.