If you've ever been to Goa, you will find that the Gambia has a similar weather and climate to Goa (India), which means long hot sunny days, low humidity and cool evenings. The Gambia is definitley a nice alternative to places like Goa, Maldives,because it's closer to US/Europe too.
I agree with the OP about the weather in Gambia being like in Goa. I traveled to Gambia for the first time in Dec last year and wasn't sure what to expect - but it was brilliant! The Gambia was more touristy than I was expecting and there are lots of places to eat yummy African food (Chicken Afra is a must).