The input of course particulate organic matter (CPOM) to streams serves as an important energy source for biota. With a changing climate rain events, droughts, and hurricanes are increasing in both intensity and frequency in tropical regions such as the Caribbean. However, the influence of these events on the timing and magnitude of CPOM inputs to streams is not clear. Here we present an 8-year time series of bi-weekly leaf litter collection from two tropical montane headwater streams in the Luquillo Experimental Forest, Puerto Rico. Leaf litter was collected along a 100 m study reach in each stream as vertically falling leaves from the canopy, riparian from lateral/hillslope inputs, and litter transported from upstream. The potential total CPOM input was assessed as a total (sum the three sources) as well as individual CPOM sources to explore temporal patterns. Additionally, the different sources of CPOM were compared to environmental variables (i.e., stream discharge, rain, wind, solar radiation) to identify potential drivers of CPOM inputs to streams. Generally, the transition between dry to wet periods resulted in pulses of total CPOM inputs across both streams. Upstream and riparian inputs were the largest contributors of CPOM although riparian and vertical inputs at times increased, such as after hurricanes impacted the forest. Upstream and riparian inputs correlated positively with increases in rain and wind while vertical inputs were minimal and not correlated to any of the environmental variables. Collectively, these results suggest the timing and magnitude of CPOM inputs is variable but unique across different climatic events. Moreover, the whole watershed landscape must be taken into perspective when quantifying organic matter inputs as they go beyond the immediate riparian zone.