Wind direction tells where the wind is blowing from. For example, a north wind is coming from the north and is blowing towards the south. There are four components of wind that are measured: direction, speed, character (i.e. whether it's a gust or a squall) and shifts. More weather definitions Â». : km/h. Humidity Relative humidity is a percentage of water vapour per area at a specific temperature. Relative humidity is calculated at all times of the year, but the humidex is usually only given in the warmer months from May to September.