Southeast Florida has a wet season and dry season based on the rainfall amount. The seven months from November through May are considered the dry season. The five months from June through October are considered the wet season. Long-term averages indicate South Florida has an annual rainfall of 52 to 53 inches, with roughly three-quarters of the rainfall occurring in the wet season. Spatial variability of rainfall is wide-ranging and highly influenced by the oceans surrounding the peninsula, the large lakes within the interior of the state, as well as sea breeze and tropical storm occurrences.
Identifying trends in rainfall observations in Southeast Florida is challenging. It is difficult to attribute the historical changes in rainfall to climate change directly, as rainfall changes could be cyclical and affected by intra and multi-decadal natural climate variability, such as El-Niño and other recurrent climate phenomena. Global climate models used to develop future rainfall projections currently lack the sufficient resolution to incorporate finer-scale regional climate influences that influence rainfall patterns in Southeast Florida, and hence projections are not provided in this set of indicators.
Analysis of observed rainfall trends from 1895 to 2019 is presented in the charts below per county and per season (dry and wet), as well as total annual values, exhibiting, in most cases, significant natural variability but no systematic trends. Changes in rainfall patterns could impact stormwater volumes and the amount of available fresh water, potentially causing more frequent flooding events or prolonged periods of drought.