When Is the Best Time
Best months and low season are May and June - fewer people. If there isn't any cruise ship in Roseau harbour it is best from December until April, the "dry season". Avoid weekends.
The dry season last from December until April/May. This is also the peak tourist and cruise ship season. Anyway rain can always occur. Rainy season from June until November with the possibilities of hurricanes and flash floods. The climate is humid tropical. The driest month is March and the wettest is August.
Where and Tips
It is a very popular pool with a 12 m waterfall. The pool is deep enough for swimming. It is a short 15 min. walk with great views. Usually it is a circular path but under construction at the moment (Feb.16).
You need to pay an entrance fee therefore I recommend a site pass for a week. Most of the attractions are included except e.g. waterfalls on a private property like Jacko or Spanny. Combine this two falls with Emerald Pool.
At the huge parking area are some souvenir stalls from local people. There is a sheltered picnic area and you can get beverages and wraps.