Johannesburg sits at 26.2°S latitude on the Highveld plateau at 1,753m elevation, giving it a subtropical highland climate with mild, dry winters and warm, wet summers. The city averages 713mm of rainfall annually, nearly all falling during the October-March summer thunderstorm season. With roughly 3,200 hours of sunshine per year, Johannesburg is one of the sunniest major cities in the world. The high altitude means UV levels are extreme year-round and temperatures drop sharply after sunset even in summer. This guide provides exact monthly data to plan your trip.
Johannesburg Weather by Month: Temperature, Rainfall, and Sunshine
January
High 26°C (79°F), Low 15°C (59°F), Rainfall 125mm over 15 days, Humidity 72%, Sunshine 250 hours. January is hot and wet with afternoon thunderstorms typically building from 2pm onward. Rain comes as short, intense downpours lasting 30-60 minutes followed by clearing skies. The UV index sits at 11+ (extreme). Bring sunscreen and a rain jacket and plan hiking before midday.
February
High 26°C (79°F), Low 15°C (59°F), Rainfall 90mm over 11 days, Humidity 71%, Sunshine 235 hours. February is similar to January but with slightly less rain. Afternoon storms remain the pattern. The city is green and lush with jacaranda trees in leaf but not yet in bloom. Hotel rates are moderate as this is mid-summer season.
March
High 25°C (77°F), Low 14°C (57°F), Rainfall 85mm over 10 days, Humidity 68%, Sunshine 240 hours. March marks the transition away from peak summer. Rainfall decreases, evening temperatures start to cool, and the humidity drops. The last month with consistent afternoon thunderstorms. A pleasant month for outdoor activities.
April
High 22°C (72°F), Low 10°C (50°F), Rainfall 40mm over 7 days, Humidity 63%, Sunshine 235 hours. April brings autumn with noticeably cooler nights (10°C/50°F) and a sharp drop in rainfall to just 40mm. Days remain warm and sunny. The dry season begins. Pack a jacket for evenings but enjoy clear blue skies during the day.
May
High 19°C (66°F), Low 6°C (43°F), Rainfall 15mm over 3 days, Humidity 56%, Sunshine 275 hours. May is the start of winter proper. Daytime temperatures are pleasant at 19°C but nights can drop to 6°C. Rainfall drops to nearly nothing (15mm). The air is crisp and dry. Sunshine hours peak. Bring warm layers for mornings and evenings.
June
High 17°C (63°F), Low 4°C (39°F), Rainfall 8mm over 2 days, Humidity 50%, Sunshine 280 hours. June is the coldest month. Daytime reaches 17°C but nights drop to 4°C with occasional frost in outer suburbs. Rainfall is negligible at 8mm. The sky is cloudless and deep blue. Sunshine hours are at their maximum. Pack a heavy jacket and gloves for early morning game drives.
July
High 17°C (63°F), Low 4°C (39°F), Rainfall 5mm over 1 day, Humidity 47%, Sunshine 290 hours. July is the driest month with only 5mm of rain. Days are cool but sunny with the highest sunshine hours of the year. Nighttime temperatures drop to 4°C and frost is common. The dry air and clear skies make this a popular month for photographers.
August
High 20°C (68°F), Low 6°C (43°F), Rainfall 8mm over 2 days, Humidity 45%, Sunshine 295 hours. August brings the first hint of spring. Daytime temperatures climb to 20°C but nights remain cold at 6°C. The air is extremely dry (45% humidity). August winds can be strong, especially on the East Rand. The jacaranda buds begin to swell but won’t bloom until October.
September
High 23°C (73°F), Low 10°C (50°F), Rainfall 25mm over 4 days, Humidity 46%, Sunshine 275 hours. September is spring and one of Johannesburg’s best months. Days warm to 23°C and nights moderate to 10°C. The first spring rains arrive but are light. The city’s parks burst into green. The combination of warm days, cool nights, and low humidity is ideal for sightseeing.
October
High 25°C (77°F), Low 12°C (54°F), Rainfall 72mm over 9 days, Humidity 53%, Sunshine 260 hours. October brings the jacaranda bloom, turning entire suburbs purple. Temperatures climb to 25°C and thunderstorms return with the first heavy summer rains. The contrast of purple jacarandas against blue Highveld skies makes this the most photogenic month. Book accommodation early.
November
High 25°C (77°F), Low 14°C (57°F), Rainfall 115mm over 14 days, Humidity 60%, Sunshine 240 hours. November is hot with afternoon thunderstorms becoming a daily occurrence. The jacarandas fade but the city remains green. Rainfall more than doubles from October to 115mm. UV index reaches extreme levels. Carry a rain jacket even on sunny mornings.
December
High 26°C (79°F), Low 15°C (59°F), Rainfall 120mm over 16 days, Humidity 65%, Sunshine 250 hours. December is peak summer with warm days, mild nights, and daily afternoon storms. The city empties as residents head to the coast. Hotel rates drop and roads are quiet. Christmas decorations appear in shopping malls. The combination of warm weather and low crowds makes this a good time to visit if you don’t mind afternoon rain.
Johannesburg Climate Data at a Glance
| Month | High (°C) | High (°F) | Low (°C) | Low (°F) | Rain (mm) | Rain Days | Sun (hrs) |
|---|---|---|---|---|---|---|---|
| Jan | 26 | 79 | 15 | 59 | 125 | 15 | 250 |
| Feb | 26 | 79 | 15 | 59 | 90 | 11 | 235 |
| Mar | 25 | 77 | 14 | 57 | 85 | 10 | 240 |
| Apr | 22 | 72 | 10 | 50 | 40 | 7 | 235 |
| May | 19 | 66 | 6 | 43 | 15 | 3 | 275 |
| Jun | 17 | 63 | 4 | 39 | 8 | 2 | 280 |
| Jul | 17 | 63 | 4 | 39 | 5 | 1 | 290 |
| Aug | 20 | 68 | 6 | 43 | 8 | 2 | 295 |
| Sep | 23 | 73 | 10 | 50 | 25 | 4 | 275 |
| Oct | 25 | 77 | 12 | 54 | 72 | 9 | 260 |
| Nov | 25 | 77 | 14 | 57 | 115 | 14 | 240 |
| Dec | 26 | 79 | 15 | 59 | 120 | 16 | 250 |
Johannesburg Weather Patterns and What to Expect
Johannesburg’s high-altitude subtropical climate produces two sharply different seasons. The dry winter (May-September) brings cloudless skies, daytime temperatures of 17-23°C, and cold nights dropping to 4°C with frost. The wet summer (October-April) delivers 25-26°C highs, afternoon thunderstorms, and 85% of annual rainfall. The city records over 3,200 sunshine hours annually, making it one of the world’s sunniest major cities.
First-time visitors underestimate Johannesburg’s winter cold. The high altitude (1,753m) means temperatures drop fast after sunset. Hotels and restaurants often lack central heating. Pack a heavy jacket, gloves, and a scarf for June-July visits. The UV index sits at extreme levels (11+) year-round due to altitude. Apply SPF 50+ sunscreen and wear a hat even on cloudy days.
Summer thunderstorms are spectacular but predictable: they build from late morning, peak between 3pm-6pm with lightning displays across the Highveld sky, and clear by sunset. Plan outdoor activities for mornings. The lightning is serious; avoid open spaces and tall objects during storms. The rainy season transforms the brown winter landscape into lush green within weeks of the first October rains.
