For drought monitoring related to vegetation, I need to calculate Standardized Percipitation INdex for a given area. Where can I find the most real-time percipitation data to do this? The best I've found is CHIRPS data, which has a latency of one month. Is there any freely available data that is more up-to-date?
There are more up-to-date datasets that are available after registration and acceptance of the respective data usage licences.
E.g. two satellite-derived products
For a more comprehensive overview, including evaluation against rain gauge data, see Beck et al. 2017.
Beck, H.E., Vergopolan, N., Pan, M., Levizzani, V., van Dijk, A.I., Weedon, G.P., Brocca, L., Pappenberger, F., Huffman, G.J. and Wood, E.F., 2017. Global-scale evaluation of 22 precipitation datasets using gauge observations and hydrological modelling. Hydrology and Earth System Sciences, 21(12), pp.6201-6217.