“Sunny day flooding” is flooding where water comes right up from the ground, hence the name, and yes, it can certainly rain during sunny day flooding, and yes, that makes it worse. Sunny day flooding happens in many parts of Miami, but it is especially bad in Sunset Harbour, the low-lying area on Miami Beach’s west side.
The sea level in Miami has risen ten inches since 1900; in the 2000 years prior, it did not really change. The consensus among informed observers is that the sea will rise in Miami Beach somewhere between 13 and 34 inches by 2050. By 2100, it is extremely likely to be closer to six feet, which means, unless you own a yacht and a helicopter, sayonara. Sunset Harbour is expected to fare slightly worse, and to do so more quickly.