Climate Insights for Grootvlei

Gert Sibande District Municipality, Mpumalanga, South Africa

Hottest
December
27°C peak
Coldest
July
3°C low
Wettest
December
147mm rain
Best to Visit
March, April, September
Mild temps & low rain

Climate Overview

The climate in Grootvlei is temperate. The average annual temperature is 17°C and approximately 744mm of precipitation falls per year. December is the wettest month, receiving around 147mm of rainfall. Grootvlei is in the Southern Hemisphere. The seasons are reversed — summer runs from December to February, while winter falls between June and August. The summer months are: December, October, November. The coldest months are July, June, August, when temperatures can drop to 3°C.

Temperature

10° 15° 20° 25° 30° Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Max: 26° Average: 20° Min: 15° Feb Max: 26° Average: 20° Min: 15° Mar Max: 26° Average: 19° Min: 13° Apr Max: 23° Average: 16° Min: 10° May Max: 22° Average: 13° Min: 6° Jun Max: 19° Average: 10° Min: 3° Jul Max: 19° Average: 10° Min: 3° Aug Max: 22° Average: 14° Min: 6° Sep Max: 26° Average: 18° Min: 10° Oct Max: 27° Average: 19° Min: 12° Nov Max: 27° Average: 20° Min: 13° Dec Max: 27° Average: 21° Min: 15°
Max
Average
Min

Temperatures in Grootvlei vary considerably across the year, with a 24°C difference between the coldest and warmest months. The warmest month is December, when average highs reach 27°C and the mean temperature sits around 21°C. July is the coolest month, with minimum temperatures around 3°C and an average of 10°C. On average, daily temperatures fluctuate by about 14°C between overnight lows and afternoon highs. The sharpest temperature change occurs between August and September, with a 4°C shift in average temperatures.

Precipitation

0mm 25mm 50mm 75mm 100mm 125mm 150mm Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Precipitation: 130mm Feb Precipitation: 105mm Mar Precipitation: 66mm Apr Precipitation: 64mm May Precipitation: 19mm Jun Precipitation: 6mm Jul Precipitation: 5mm Aug Precipitation: 2mm Sep Precipitation: 15mm Oct Precipitation: 67mm Nov Precipitation: 117mm Dec Precipitation: 147mm
Precipitation

Grootvlei is a relatively dry area, receiving approximately 744mm of precipitation annually, which averages out to around 62mm per month. The wettest month is December, averaging 147mm of rainfall. January and November also tend to see above-average precipitation. The driest month is August, with just 2mm. That's 145mm less than December, the wettest month. Rainfall is heavily concentrated in certain months, creating a distinct wet and dry season. Visitors should plan around these patterns, as the difference between peak and low months is dramatic.

Wind

0km/h 5km/h 10km/h 15km/h 20km/h 25km/h Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Wind Speed: 17km/h Feb Wind Speed: 17km/h Mar Wind Speed: 16km/h Apr Wind Speed: 16km/h May Wind Speed: 14km/h Jun Wind Speed: 16km/h Jul Wind Speed: 17km/h Aug Wind Speed: 19km/h Sep Wind Speed: 21km/h Oct Wind Speed: 20km/h Nov Wind Speed: 20km/h Dec Wind Speed: 19km/h
Wind Speed

Grootvlei is mildly breezy, with an average annual wind speed of 18km/h. For context, sustained winds below 12km/h are generally light, while anything above 25km/h is considered strong. The windiest month is September, averaging 21km/h, noticeable enough to affect lighter outdoor activities. The calmest conditions occur in May, with average winds dropping to 14km/h, making it an ideal period for wind-sensitive activities. There is moderate seasonal variation in wind speed, with a 7km/h gap between the calmest and windiest months.

Seasons

Winter
Dec 21
Spring
Sep 23
Summer
Dec 21
Autumn
Mar 20

89 days until Winter

It is currently autumn in Grootvlei, which began on March 20, 2026. Grootvlei is in the Southern Hemisphere, where the seasons are reversed — spring starts in September, summer in December, autumn in March, and winter in June. The warmest period peaks in December at around 27°C, while the coldest stretch bottoms out in July near 3°C. Winter is next, beginning on June 21, 2026 — 89 days from now.

Spring

Temperatures range from 10 to 27°C. Precipitation is moderate at around 200mm for the season, averaging 67mm per month. Winds are moderate at around 20km/h. Light layers work well as temperatures warm through the season — a great time to be outdoors.

Summer

Temperatures range from 15 to 27°C. Rainfall is heavy, totalling around 382mm across the season with a monthly average of 127mm. Winds are moderate at around 17km/h. Light, breathable clothing is ideal — perfect conditions for outdoor activities.

Autumn

Temperatures range from 6 to 26°C. Rainfall is relatively light, with around 149mm over the season and a monthly average of 50mm. Winds are moderate at around 15km/h. Layered clothing works best as temperatures gradually cool — enjoy the crisp air and changing scenery.

Winter

Temperatures range from 3 to 22°C. Precipitation is minimal, with only around 13mm for the entire season. Winds are moderate at around 17km/h. A light jacket or sweater is usually sufficient, though cooler evenings may call for an extra layer.

Best Time to Visit

Jan 20°
Feb 20°
Mar 19°
Apr 16°
May 13°
Jun 10°
Jul 10°
Aug 14°
Sep 18°
Oct 19°
Nov 20°
Dec 21°

The best time to visit Grootvlei is during March, April, September and October, when the weather is most comfortable for travellers. During these months, average temperatures hover around 18°C with modest rainfall averaging 53mm per month. By contrast, December can be uncomfortably hot with highs reaching 27°C, while July is the coldest period with lows dropping to 3°C. A light rain jacket is recommended, though showers are generally brief and shouldn't disrupt your plans.

Monthly Climate Data

The table below shows monthly climate averages for Grootvlei based on historical weather data. Min and max temperatures represent typical overnight lows and afternoon highs for each month, shown in degrees Celsius (°C). Precipitation is measured in millimetres (mm) and indicates the average total rainfall per month. Wind speed is the average sustained speed in kilometres per hour (km/h). All values are based on averages from over 10 years of historical weather data. The current month is highlighted for quick reference.

Month
Min Temperature
Max Temperature
Wind Speed
Precipitation
Snow
Jan
15 °C
26 °C
17 km/h
130 mm
0 cm
Feb
15 °C
26 °C
17 km/h
105 mm
0 cm
Mar Current
13 °C
26 °C
16 km/h
66 mm
0 cm
Apr
10 °C
23 °C
16 km/h
64 mm
0 cm
May
6 °C
22 °C
14 km/h
19 mm
0 cm
Jun
3 °C
19 °C
16 km/h
6 mm
0 cm
Jul
3 °C
19 °C
17 km/h
5 mm
0 cm
Aug
6 °C
22 °C
19 km/h
2 mm
0 cm
Sep
10 °C
26 °C
21 km/h
15 mm
0 cm
Oct
12 °C
27 °C
20 km/h
67 mm
0 cm
Nov
13 °C
27 °C
20 km/h
117 mm
0 cm
Dec
15 °C
27 °C
19 km/h
147 mm
0 cm
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Metric (°C, km/h)