**4. Conclusions**

This study presents a proposed approach to evaluate drought characteristics using multiple climate models for multiple timescales under a context of global warming. The method of unequal weights is proposed to reduce uncertainty of climate projections. The Mann–Kendall and Sen's slope methods are then applied to find the trends in drought characteristics for multiple timescales of 1, 3, 6, 9, 12, and 24 months with six climate projections. The unequal weights are proposed on the basic of rank sum of each climate model. Vu Gia-Thu Bon basin located in central Vietnam is selected to implement this study as a pilot basin. The major findings of the present study can be exposed as an impulse of the precipitation simulations using unequal weights for multiple climate models. Under the scenarios of RCP4.5 and RCP8.5, there are no events classified as "extremely wet" and "extremely dry" for the all stations during 2021–2050 for SPI-1, SPI-3, SPI-6, SPI-9, SPI-12 and SPI-24 indices. A higher magnitude of the drought conditions in the north and east of the basin compared toother areas is found out. Under the RCP4.5 scenario, more importantly, timescales are longer, and the intensity of moderately dry is stronger. Moreover, the occurrence of moderately wet events is smaller than that of moderately dry under the RCP4.5 scenario during 2021–2050 in the same timescales. Under the RCP8.5 scenario, events classified as "extremely wet", "extremely dry", "very wet" and "severely dry" are expected to rarely occur.

**Supplementary Materials:** The following are available online at http://www.mdpi.com/2225-1154/6/4/79/s1.

**Funding:** This research received no external funding.

**Conflicts of Interest:** The author declares no conflicts of interest.
