Nieu Bethesda is part of the semi-arid Great Karoo climactic region. It has long hot summers and moderate winters. In South Africa, the summer and winter months are opposite to those in the Northern Hemisphere. Summers in Nieu Bethesda run between October and April.
Information on temperatures comes from the closest weather station at Graaff-Reinet, only 50km away. Average midday temperatures range from 17.4°C in June to 30.4°C in January. Summers are hot and dry, but the weather is bearable. July is the coldest month with temperatures dropping to an average of 2.5°C at night.
Most of the 255mm of rain per year falls in the autumn months from March to June. The lowest rainfall received is 6mm in July. The highest is 50mm in March.