Influenza is a contagious respiratory illness caused by influenza viruses that affects 5-20% of the U.S. population each year, resulting in more than 200,000 hospitalizations and 36,000 deaths on average. During periods of peak influenza virus activity, patients exhibiting influenza like illnesses can account for up to 7.5% of all patient visits, placing a significant strain on clinics and hospital emergency rooms. Influenza in temperate regions exhibits a pronounced seasonality that has been well described. A number of hypotheses have been proposed to explain this seasonality, and recent studies have demonstrated both a temperature threshold effect (in animal studies) and a significant correlation between latitude and the timing of annual influenza epidemics. These results suggest that environmental drivers play a role in influenza transmission, innate immunity, and/or virus-host interaction, and could be used to forecast the date of peak influenza activity. In particular, the average difference in peak week for southern versus northern cities is approximately 60 days, which closely matches phenological patterns in the U.S., suggesting a potential link between the two. The lack of suitable environmental datasets and reliable measures of influenza activity has historically limited research on this topic. The recent availability of data on influenza activity from CDC and the development of key environmental datasets on climate and phenology using the NASA Terrestrial Observation and Prediction System offer a unique and promising opportunity to apply data from NASA satellites and modeling frameworks to understand environmental drivers affecting influenza transmission patterns, and the timing of peaks in influenza activity. We propose to apply these capabilities to develop a prototype influenza forecasting system that incorporates data on current influenza activity, climate, and phenological indicators, and to work with CDC to identify a strategy for integrating these forecasts into the CDC influenza surveillance systems.