Cartagena though being located on the coast has a hot semi-arid climate. Some respite is provided from the oceanic winds though. Rainfall expectancy is quite low throughout the year and the average annual temperature is around 18 degree Celsius.
If you want to soak in the fun and excitement of Cartagena then plan a visit during the months of February to August. This is also the peak season, so expect high tariffs and more waiting in the lines. The winters are also a best time to visit, and being off-season they are cheaper than the rest of the year.