The hydrological sector is sensitive to different meteorological conditions in various ways, which could be divided in the following groups:
- Resource allocation deals mainly with water availability. The important factors are the long term changes and variability of temperature, precipitation, evaporation and snow amount. A changing climate increases the need for water management.
- Risk management deals with flash-floods and extreme river floods. Rainfall time series, in combination with projections of future precipitation changes (especially extremes), can be used to calculate the risk of flooding. For river flows there is also a need for estimates of river discharge.
- Ecological status consists of both biological status and water quality. Important factors are lake temperature and stratification, ice cover and precipitation. Lake models are used to calculate nutrient flow, stratification etc.
- Water related industries include industries with a large need of water, hydro power production and the drinking water itself. Important factors are mean and extreme precipitation and snow cover.
Many meteorological events that are important for the hydrological sector are local in both space and time. Extreme precipitation is for example an event that could be both short-lived and limited in space. Climate models with high spatial resolution have a better chance of capturing extreme events than models with lower resolution. Hydrological models, which are used to simulate river discharge, are also very reliant on precipitation data with high spatial and temporal resolution.
Policies related to hydrology, for example transferring water from one hydrological basin to another, are managed by national governments. Thus policymakers may be interested in variables such as projected average yearly rainfall, drought frequency or projected seasonal changes. As often the water distribution is managed by private companies, they also may be interested in questions such as the evolution of the water demand for irrigation or other uses. Other companies involved in the management, building or maintenance of dams and similar infrastructures may be interested in future river flow projections, and also in precipitation extremes. The agricultural sector is strongly related to the hydrological sector, so the users of this sector can also be interested in specific information about hydrology.