General climatic conditions

The JIA Scheme falls within a hyper-arid part of the Orange-Senqu River Basin and experiences a harsh climate. Some of the main characteristics of the prevailing climatic conditions for the JIA are provided below:

Temperature Evaporation and Rainfall
Rainfall and evaporation
A relatively cool season prevails from May to August, with mean monthly minimum temperatures of below 10°C during which frost could occur on some days. A very hot season occurs from November to February, when mean monthly maximum temperatures rise to 35°C, but absolute daily maximum temperatures can rise up to 47°C. The JIA has a mean annual rainfall of just above 60 mm per annum which is insignificant compared with an average Potential Evaporation of 1 570 mm per annum and an average S-pan Evaporation of 2650 mm per annum.


Weather forecast for Noordoewer and Vioolsdrift

Weather stations

Weather monitoring

An automated weather station was erected at a suitable site near the JIA office, which is approximately midway into the scheme and therefore, from a climate point of view, fairly representative of the conditions in the scheme.

Information is transmitted via radio at 15 minute intervals to the JIA server, and then sent together with the soil probe data to a online server.

The position of the erected JIA weather station is indicated on the map below, as well as the position of the Department of Water Affairs (DWA) of South Africa’s weather station at the scheme’s weir. The DWA station was however discontinued in 2000.



Weather monitoring

The map below provides the positions of the JIA and Department of Water Affairs of South Africa’s weather stations (D8E001). The JIA station’s near real-time data is available by clicking on the JIA station’s marker and selecting the appropriated link. The historic rainfall data and graph of D8E001 can also be accessed by clicking on the marker and selecting the link to the DWA Hydstra Website. The map also provides the position and names of the canals as well as detailed information about the irrigated fields, by clicking on the respective elements.

Legend: Stations Weather Station Stations Canals Stations Irrigated fields