Listen, I'm a Bonao expert. it's a bold statment, i know, so bare with me for a minute. Stay away from Bonao from January 1st to December 31st. it rains, it pours, it comes down sideways in sheets so thick that you cannot see your hand or wallet. And just when you think the sun is going to make an appearance, it rains and pours some more. i'm not kidding. Bonao sits in a valley, surrounded by ominous dark clouds of acid rain that makes Lord of the Rings novels seem like utopia in comparison. I sat in Bonao from June 1st 1978 until September 14th 1980 without seeing the sun more than two or three times, and even then, it came out just long enough to allow one to get a good gander at the rushing, torrential rivers outside our front door. In front of our house i saw a river 6 feet high go rushing by with cattle, outhouses, chicken shacks, cars, motoconchos, fruit stands, and corregated tin roofs with people surfing atop of them...heading to work. i'm not kidding.
If you want to see a non-stop onslaught of torrential downpours then by all means, go to Bonao. If you want to spend your afternoons surfing streets filled in a five-feet diluge of street trash and 6-foot waves breaking 50 yards out, then by all means go to Bonao. if you want to see dark ominous clouds, so thick that sunlight cannot even begin to penetrate them, then by all means, go to Bonao. if you want to see chickens, horses, prostitutes and cattle surfing down the street, taking shortcuts to nearby farms and brothels, then by all means, go to Bonao.
However, if its sunshine, bikinis, and Pina Colodas served out of pineapples and coconuts that you are looking for, then do yourself a favor and head for the North Coast--Cabarete, Cabrera, Las Terrenas, etc. and sit on the beach and watch cirrus clouds wisp like whip cream above your head as you sip local rum out of pineapples.
Frank