Weather in Johannesburg in January
South Africa · 20-year averages, January
A good month. January is a solid month to be in Johannesburg. You should expect rain on 20 days of the month, which is more days wet than dry.
January ranks 11 of 12 — near the bottom of Johannesburg's year. August is the month that works, and the swing between the two is 33 points, which is a different holiday rather than a slightly better one. Worth keeping in perspective: January is the weakest month of Johannesburg's year and it is still a perfectly good one. The downside here is small.
Rain on 20 of the month's 31 days, 3 of them heavy. At that frequency a wet-weather backup is not a contingency, it is the itinerary — book the indoor things first and treat the clear days as the bonus. Nothing specialised needed — this is the month you pack for the trip rather than for the weather.
What the averages hide
Averages flatten a month, and this one hides a few things: 5 days top 30 °C — hot spells arrive, but they break. Across the twenty years measured, the hottest January day reached 37.3 °C and the coldest night fell to 5.5 °C, and the wettest single day dropped 62 mm — roughly 50% of the month's rain in one day.
January is moderately variable: 41 mm in the driest year against 272 mm in the wettest, around an average of 123 mm. Roughly two Januarys in three land near that average, and the third does something else entirely.
Wind is light at 7.4 km/h, so the temperature on the page is close to the temperature on your skin, and humidity is unremarkable at 65%.
How January sits in the year
Temperatures hold steady either side: 26.8 °C in December, 26.9 here, 26.9 in February. Nothing about the timing within the month matters much.
Daylight in January
January is at or near the longest days of Johannesburg's year: 13.6 hours of daylight, losing 0.4 hours across the month. Evenings are the real gain — dinner outdoors still happens in full light.
An inland climate
With no coast nearby, the year swings a fair way — 25.6 °C between the warmest afternoons and the coldest nights, wider than any coastal city at this latitude would manage. At 1767 m, altitude is doing as much work here as latitude: thinner air means fierce sun by day and heat that leaves the moment it sets.
How busy it gets
Off season. The genuine off season: cheapest by a distance, with the caveat that some tours and restaurants close entirely.
Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.
January in Johannesburg versus nearby
If Johannesburg is one option among several, the nearby comparison is worth making. Pretoria is the weaker option in January — 3.5 °C warmer, the same number of rain days. Pietermaritzburg is close enough to be a coin toss — within a degree on temperature, 5 days more rain.
So: January is a compromise. August is 33 points better and is what Johannesburg is actually like at its best — worth moving the trip for if that is possible, and worth adjusting expectations for if it is not.
Every month in Johannesburg
| Month | High °C | Low °C | Rain days | Rain mm | Humidity % | Daylight h | Score |
|---|---|---|---|---|---|---|---|
| January | 26.9 | 13.8 | 20 | 123 | 65 | 13.6 | 65 |
| February | 26.9 | 13.5 | 16 | 82 | 64 | 13 | 73 |
| March | 25.7 | 11.9 | 14 | 73 | 63 | 12.3 | 76 |
| April | 22.8 | 8.9 | 8 | 43 | 62 | 11.5 | 86 |
| May | 20.4 | 5.1 | 2 | 16 | 54 | 10.9 | 97 |
| June | 17.4 | 2 | 1 | 7 | 55 | 10.5 | 90 |
| July | 17.5 | 1.4 | 1 | 3 | 49 | 10.6 | 90 |
| August | 21 | 4 | 1 | 7 | 44 | 11.2 | 98 |
| September | 25.4 | 7.6 | 2 | 16 | 39 | 11.9 | 97 |
| October | 27 | 10.5 | 10 | 57 | 48 | 12.7 | 83 |
| November | 27 | 12 | 16 | 89 | 57 | 13.4 | 72 |
| December | 26.8 | 13.5 | 20 | 127 | 63 | 13.8 | 65 |
See all twelve months in Johannesburg, or where else to go in January.
Planning the rest of the trip
- Flight time to Johannesburg how long you are actually in the air
- Johannesburg time zone and the difference from home
- Days until your trip count down to the departure date