Climate
Nestled within the southern subtropical high-pressure belt, the Richtersveld National Park (RNP) wears its aridity as a badge of honor. As the sole national park straddling both summer and winter rainfall belts, our landscape experiences two very distinct climates.
To the west, a warm temperate winter rainfall region unfurls, stretching from the southern mountain ranges to the horizon. Here, rainfall graces the land in seasonally. Yet, venture deeper into the park, and you’ll encounter a non-seasonal rainfall pattern.
To the east lies the subtropical summer rainfall domain, where temperatures rise, and humidity retreats. Our mean annual rainfall, a testament to this duality, varies across the park, capturing the essence of both summer and winter deluges. Rain gauges, scattered like sentinels, stand ready to record this mosaic of precipitation.
The mean annual rainfall for the south-western mountainous area (Paradyskloof) of the park was 114 mm from 2000 – 2016, with a range of 58 mm – 275 mm, whereas in the interior (Tatasberg) the mean annual rainfall for the same period was 38 mm, with a range of 0 mm – 163 mm. The highest total annual rainfall recorded for the park was 275 mm in the south-western mountains (Paradyskloof) in 2006.
The majority of the park receives winter rainfall (from May to September) which is usually soft rain spread out over the mountainous area, while summer rainfall (October – April) is not uncommon with rain often falling in intensive thunderstorms which can be very patchy and localized.
Furthermore, moisture is brought in by the western fog, known locally as the Malmokkie, rolling in from the cold Atlantic Ocean seaboard which is cooled by the Benguela Current. The fog, as a source of moisture for plant growth along the West Coast, is more reliable in terms of frequency and predictability of occurrence than rainfall. The warmer easterly winds, usually around August, dry out the veld and can destroy the annual plants, which are crucial fodder for livestock.
Temperatures in the park vary between extremes – reaching above 50°C in summer and dipping to freezing depths come winter nights.
In general, the park is experiencing warmer temperatures during the day than at night, and the difference in these temperatures can be quite drastic. The minimum and maximum temperatures are recorded daily at Sendelingsdrift and the mean minimum and maximum temperatures for the past nine years (2008 – 2016) were 14°C and 29°C respectively. Temperatures can easily rise above 50°C in the summer months and plunge to freezing point on winter nights. The mean maximum temperature rapidly declines from April to June followed by a gradual increase to a maximum in February.
The decline in maximum temperatures could possibly be a result of the influence that the wind has as it could carry advective heat from warmer areas or because of adiabatically heated air in the form of bergwinds. The Richtersveld is characterized by relatively high wind speeds, overall ranging from an average of 7km.hr-1 in January to 4km.hr-1 in June.