24 T.A. Cinco et al. / Atmospheric Research 145–146 (2014) 12–26 Table 3 Extreme rainfall event frequency and intensity values for synoptic weather stations in the Philippines. indicate, as our results have, that Baguio is likely becoming wetter. Interestingly Iloilo and Tacloban are two of the few stations to show a significant increase in both intensity and frequency of extreme rainfall events in this study and both these stations were also found by Lyon and Camargo (2008) to have above average seasonal rainfall signals during El Niño development phases, maintaining higher levels of precipitation at a time of generally decreasing trends. Another station is at Infanta and similarly to Tacloban this is located on the eastern seaboard of the Philippines which Chang et al. (2005) found to be affected by heavy rain brought by strong onshore winds of the northeast monsoon, perhaps explaining this observation. It is worth noting however that the earlier studies discussed above use slightly different datasets to those used in this study and investigate seasonal variations as opposed to long term trends so direct comparisons are not wholly appropriate but this does provide some indication of the level of national and sub-national consistency of the results of this study. 5. Conclusion This paper has presented temperature indicators which suggest that the climate in the Philippines, like much of the rest of the region and the globe, is warming. Across a range of climatic indicators presented and discussed here (e.g. Tmean, Tmax and Tmin), an increasing trend of anomalous temperatures versus the 30 year normal period of 1961–1990 can be observed. In addition, daily temperature extremes reveal more hot days and fewer cooler nights versus the mean from the normal period of 1961–1990 for much of the Philippines, with the majority of these results statistically significant. These trends, derived from directly observed data, contribute to a body of evidence which is consistent with a global climate which is warming above any normal variation we might expect to see since the mid-20th century. Less clearcut is the apparent trend in extreme rainfall events across the country with only a handful of synoptic stations recording a statistically significant increase in intensity and frequency of extreme rainfall events. Little discernible spatial coherence at the sub national level for any of the temperature or rainfall indicators was found which points to the heterogeneous nature of the climate system in the Philippines. Whilst orographic effects appear to be minimal (see stations at Baguio and Malaybalay), the effects of monsoon moisture laden winds may account for extreme rainfall indicators on the Pacific coast showing as significantly positive, and the effects of passing tropical cyclones cannot be ruled out. Stations which showed an increase in both frequency and intensity of rainfall extremes are located in the typhoon belt of the Philippines and the investigation of any correlation between extreme indices and tropical cyclone activity could be a useful future research direction. If the temperature in the Philippines continues with the upward trend seen here, notwithstanding continued inter annual variability, there may be serious implications for the economic and social development of this archipelagic nation. If, according to Griffiths et al. (2005) increasing temperature trends can be an indicator of the probability of more frequent extreme weather events, then this could suggest that the Philippines should be prepared for additional climate change impacts. Continued and increased exposure to the effects of a warming climate – disrupted growing seasons, changes in the occurrence of vector borne diseases and the threat of severe weather events (the impacts of which were painfully revealed following Typhoon Haiyan) – continues to pose a real development challenge in the Philippines. It is hoped that this study and others like it can form an evidence base for appropriate action to address and prepare for some of these impacts so as to avoid the worst of the damage to its emerging economy and the communities who will bear the brunt. This study builds on earlier efforts to provide a basis for the on-going monitoring of climatic trends and extremes and should be considered a reference point for future analysis of precipitation and temperature trends in the Philippines. Acknowledgements The data used in this research was gathered from PAGASA's historical records and analysed, in part with the support of the Government of the Philippines and the Millennium Development Goal Fund (MDGF) 1656 “Strengthening the Philippines Institutional Capacity to Adapt to Climate Change”, a three-year programme funded by the Government of Spain through the United Nations Development Program (UNDP) Philippines and other UN agencies (UNEP, FAO, WHO, UN Habitat). The authors also wish to acknowledge the support of the Oscar M. Lopez Center for Climate Change Adaptation and Disaster Risk Management Foundation.