The average annual rainfall for Mlawula is estimated to be in the region of 500 to 600 mm. It is possible that the Ndzindza plateau (which forms the eastern half of the reserve) receives a higher rainfall, with the Siphiso Valley being slightly dryer due to a rain shadow effect. Temperatures vary considerably between seasons and have high diurnal variation. Mid-winter average minimum and maximum temperatures are 10°C and 26°C respectively, and mid-summer temperatures 22°C and 36°C respectively. Humidities vary considerably, with monthly average humidities at 8.00 am being highest in autumn and lowest in spring, and at 2.00 pm being highest in late summer and lowest in mid-winter.