Heavy rainfall in Metro Manila especially during peak periods causes paralysis in the overall transportation system. Among the most affected by the disruptions caused by bad weather are the working commuters who then attempt to mitigate the effects of these delays by modifying their trip decisions. This research presents an analysis of how rainfall influences the travel mode choice and departure time of work-to-home commuters from Ortigas CBD. The primary data collection for this research was done by administering a questionnaire survey in December 2016, gathering information from a total of 300 respondents. The respondents were mostly young workers from ages 21 to 30 with a mean income of 25,000. The analysis using Wilcoxon test of significance reveals that the fare, travel time, walking time, waiting time, as well as perceptions of service reliability, comfort and safety and security of the transport modes servicing Ortigas CBD significantly change during heavy and intense rainfall compared to no rain conditions. Fare and travel time are the main considerations of the respondents in choosing their preferred mode during no rain and light rainfall conditions but their priorities shift toward comfort and service reliability during heavy and intense rainfall consequently affecting their mode choice. The level of switching to alternative public transport modes is at 17.67%, 39.33% and 44.67% during light rainfall, heavy rainfall and intense rainfall respectively, with P2P buses, ordinary taxis, Grab taxis and GrabCar/Uber services gaining patronage while aircon buses, jeepneys, FX/vans and MRT-3 lose their passengers. The analysis using binomial logistic regression reveals that commuters choose to shift to another mode during heavy and intense rainfall because of the decrease in the service reliability of their usual mode.