A navigation apparatus comprising: a processing resource arranged to support, when in use, an operational environment, the operational environment supporting a route calculator, a time estimation module, a route segmentation module, and a weather data processing engine; a user interface module; a map database comprising geospatial data; the route calculator arranged to calculate, when in use, a route between a first location and a second location at a particular journey start time; the time estimation module arranged to estimate a time at which a user will be present at a location along the route; the route segmentation module arranged to divide the route into a plurality of route parts and to obtain from the time estimation module at least one time of presence associated with at least one of the plurality of route parts; the weather data processing engine arranged to provide weather data associated with a route part of the plurality of route parts in respect of the time of presence associated with the route part; and the user interface module arranged to communicate to the user the weather data in respect of a number of the plurality of route parts and at respective times of presence associated with the number of the plurality of route parts, the weather data being communicated graphically in combination with a map which is divided into slices conforming to the route parts to show, per each slice, weather conditions outside the route that have been or will be missed at the respective times of presence associated with the respective route part, and wherein the user interface module is further arranged to receive an instruction to re-calculate the route after communicating the weather data by changing the journey start time, and wherein the route calculator is arranged to re-calculate the route in response to the instruction to re-calculate the route. a processing resource arranged to support, when in use, an operational environment, the operational environment supporting a route calculator, a time estimation module, a route segmentation module, and a weather data processing engine; a user interface module; a map database comprising geospatial data; the route calculator arranged to calculate, when in use, a route between a first location and a second location at a particular journey start time; the time estimation module arranged to estimate a time at which a user will be present at a location along the route; the route segmentation module arranged to divide the route into a plurality of route parts and to obtain from the time estimation module at least one time of presence associated with at least one of the plurality of route parts; the weather data processing engine arranged to provide weather data associated with a route part of the plurality of route parts in respect of the time of presence associated with the route part; and the user interface module arranged to communicate to the user the weather data in respect of a number of the plurality of route parts and at respective times of presence associated with the number of the plurality of route parts, the weather data being communicated graphically in combination with a map which is divided into slices conforming to the route parts to show, per each slice, weather conditions outside the route that have been or will be missed at the respective times of presence associated with the respective route part, and wherein the user interface module is further arranged to receive an instruction to re-calculate the route after communicating the weather data by changing the journey start time, and wherein the route calculator is arranged to re-calculate the route in response to the instruction to re-calculate the route.