Avg High
Johannesburg South in September
Avg Low
Rain
Daylight
12h
What to expect
Johannesburg South is in early spring during September, a shoulder-season stretch where conditions can nudge warmer or cooler week to week. It leans warmly comfortable through the day, and bigger day–night swings than you might expect. Conditions tend to feel steady, which makes planning simple. You get a comfortable daylight window for day trips and sightseeing.
September in context
How it compares to the rest of the year in Johannesburg South.
Hottest (avg)
#6 / 12
Wettest (avg)
#8 / 12
Daylight Hours
#7 / 12
Windiest (avg)
#1 / 12
Highest UV
#7 / 12
Most Humid
#12 / 12
Monthly climate breakdown
Temperature
- Daytime high
-
- Nighttime low
-
- Feels like (avg)
-
Sunshine
- Daylight hours
- 11.9 h
- UV index (max)
- 8
- Typical sun hours
- 06:04 - 18:01
Rain & Snow
- Total rain
-
- Rainy days
- 5 days
- Cloud cover (avg)
- 23%
Humidity & Wind
- Humidity (avg)
- 42%
- Wind (avg)
-
- Wind (max gusts)
-
Daily climate explorer
Day 15 selected for September. Typical high 24.9°C and low 9.1°C.
Typical disruptions in September
Based on 30 years of historical data, these are the disruption patterns most likely to affect plans in September.
Cold High impact
Cold feels-like nights Measures: Cold feels-like nights (min <=5C). Observed about 41% of days (12.3 days/month) in September. Historical risk signal only, not a day-by-day forecast.
12.3 days / month
~41% of days
Why this matters
- Expected days 12.3 days / month
- Probability ~41% of days
- Intensity Up to ~5°C (P95)
Cold feels-like nights are possible on ~12 days. Long outdoor blocks become harder to sustain, so layer up and keep a warm indoor fallback nearby.
Wind High impact
Strong gusts Measures: Strong gust days (>=60 km/h). Observed about 6% of days (1.8 days/month) in September. Historical risk signal only, not a day-by-day forecast.
1.8 days / month
~6% of days
Why this matters
- Expected days 1.8 days / month
- Probability ~6% of days
- Intensity Up to ~80km/h (P95)
Strong gusts are possible on ~2 days. Exposed activities and transport links are more likely to be disrupted, so keep sheltered alternatives ready.
Rain High impact
Rain disruption Measures: Likely rain disruption days. Observed about 3% of days (1.0 days/month) in September. Historical risk signal only, not a day-by-day forecast.
1.0 days / month
~3% of days
Why this matters
- Expected days 1.0 days / month
- Probability ~3% of days
- Intensity Up to ~38mm (P95)
Rain disruption risk appears on ~1 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Rain High impact
Washout risk Measures: Washout day risk. Observed about 3% of days (0.9 days/month) in September. Historical risk signal only, not a day-by-day forecast.
0.9 days / month
~3% of days
Why this matters
- Expected days 0.9 days / month
- Probability ~3% of days
- Intensity Up to ~39mm (P95)
Washout conditions are possible on ~1 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Show all disruptions (16 more)
Rain High impact
Heavy rain days Measures: Heavy rain days (>=10mm). Observed about 2% of days (0.5 days/month) in September. Historical risk signal only, not a day-by-day forecast.
0.5 days / month
~2% of days
Why this matters
- Expected days 0.5 days / month
- Probability ~2% of days
- Intensity Up to ~43mm (P95)
Heavy rain is possible on ~0 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Wind High impact
Stormy conditions Measures: Storm-impact proxy days. Observed about 1% of days (0.2 days/month) in September. Historical risk signal only, not a day-by-day forecast.
0.2 days / month
~1% of days
Why this matters
- Expected days 0.2 days / month
- Probability ~1% of days
- Intensity Up to ~68km/h (P95)
Stormy conditions are possible on ~0 days. Exposed activities and transport links are more likely to be disrupted, so keep sheltered alternatives ready.
Rain High impact
Washout run Measures: Multi-day washout runs. Observed about 0.2 days/month in September. Historical risk signal only, not a day-by-day forecast.
0.2 days / month
Probability unavailable
Why this matters
- Expected days 0.2 days / month
- Probability —
- Intensity Up to ~47mm (P95)
Multi-day washout runs are possible on ~0 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Rain High impact
Very heavy rain Measures: Very heavy rain days (>=25mm). Observed about 1% of days (0.2 days/month) in September. Historical risk signal only, not a day-by-day forecast.
0.2 days / month
~1% of days
Why this matters
- Expected days 0.2 days / month
- Probability ~1% of days
- Intensity Up to ~47mm (P95)
Very heavy rain is possible on ~0 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Wind Minor
Gusty days Measures: Gusty days (>=40 km/h). Observed about 52% of days (15.5 days/month) in September. Historical risk signal only, not a day-by-day forecast.
15.5 days / month
~52% of days
Why this matters
- Expected days 15.5 days / month
- Probability ~52% of days
- Intensity Up to ~66km/h (P95)
Gusty conditions are possible on ~16 days. Exposed activities and transport links are more likely to be disrupted, so keep sheltered alternatives ready.
Rain Minor
Wet days Measures: Wet days (>=0.1mm). Observed about 21% of days (6.4 days/month) in September. Historical risk signal only, not a day-by-day forecast.
6.4 days / month
~21% of days
Why this matters
- Expected days 6.4 days / month
- Probability ~21% of days
- Intensity Up to ~16mm (P95)
Measurable rain is possible on ~6 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Rain Minor
Rainy hours Measures: Rain-hours signal (>=3h rain). Observed about 12% of days (3.7 days/month) in September. Historical risk signal only, not a day-by-day forecast.
3.7 days / month
~12% of days
Why this matters
- Expected days 3.7 days / month
- Probability ~12% of days
- Intensity Up to ~20h (P95)
Several rainy hours are possible on ~4 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Cloud Minor
Cloudy days Measures: Cloudy days (cloud cover >=60%). Observed about 12% of days (3.5 days/month) in September. Historical risk signal only, not a day-by-day forecast.
3.5 days / month
~12% of days
Why this matters
- Expected days 3.5 days / month
- Probability ~12% of days
- Intensity Up to ~99% (P95)
Cloudy skies are possible on ~3 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Cold Minor
Cold nights Measures: Cold nights (min <=5C). Observed about 10% of days (3.0 days/month) in September. Historical risk signal only, not a day-by-day forecast.
3.0 days / month
~10% of days
Why this matters
- Expected days 3.0 days / month
- Probability ~10% of days
- Intensity Up to ~5°C (P95)
Cold nights are possible on ~3 days. Long outdoor blocks become harder to sustain, so layer up and keep a warm indoor fallback nearby.
Rain Minor
Wet most of day Measures: Wet-most-of-day signal (>=6h rain). Observed about 5% of days (1.6 days/month) in September. Historical risk signal only, not a day-by-day forecast.
1.6 days / month
~5% of days
Why this matters
- Expected days 1.6 days / month
- Probability ~5% of days
- Intensity Up to ~22h (P95)
Wet-most-of-day conditions are possible on ~2 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Cloud Minor
Mostly cloudy days Measures: Mostly cloudy days (cloud cover >=80%). Observed about 5% of days (1.4 days/month) in September. Historical risk signal only, not a day-by-day forecast.
1.4 days / month
~5% of days
Why this matters
- Expected days 1.4 days / month
- Probability ~5% of days
- Intensity Up to ~100% (P95)
Mostly cloudy skies are possible on ~1 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Humidity Minor
High humidity Measures: High humidity days (RH >=80%). Observed about 3% of days (0.8 days/month) in September. Historical risk signal only, not a day-by-day forecast.
0.8 days / month
~3% of days
Why this matters
- Expected days 0.8 days / month
- Probability ~3% of days
- Intensity Up to ~97% (P95)
High humidity is possible on ~1 days. Comfort and pace can drop quickly, so plan shorter outdoor blocks with air-conditioned backup stops.
Cloud Minor
Overcast days Measures: Overcast days (cloud cover >=95%). Observed about 2% of days (0.6 days/month) in September. Historical risk signal only, not a day-by-day forecast.
0.6 days / month
~2% of days
Why this matters
- Expected days 0.6 days / month
- Probability ~2% of days
- Intensity Up to ~100% (P95)
Overcast skies are possible on ~1 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Heat Minor
Hot days Measures: Hot days (>=30C). Observed about 2% of days (0.5 days/month) in September. Historical risk signal only, not a day-by-day forecast.
0.5 days / month
~2% of days
Why this matters
- Expected days 0.5 days / month
- Probability ~2% of days
- Intensity Up to ~31°C (P95)
Hot days are possible on ~0 days. Midday activity often needs adjustment around shade, hydration, and indoor fallback options.
Visibility Minor
Fog-likely signal Measures: Fog-likely visibility proxy. Observed about 1% of days (0.2 days/month) in September. Historical risk signal only, not a day-by-day forecast.
0.2 days / month
~1% of days
Why this matters
- Expected days 0.2 days / month
- Probability ~1% of days
- Intensity Up to ~97% (P95)
Fog-likely conditions are possible on ~0 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Other Minor
Low visibility proxy: same as fog-likely (RH ≥90% AND cloud ≥95%) — true visibility requires hourly visibility data Measures: Low visibility proxy: same as fog-likely (RH ≥90% AND cloud ≥95%) — true visibility requires hourly visibility data. Observed about 1% of days (0.2 days/month) in September. Historical risk signal only, not a day-by-day forecast.
0.2 days / month
~1% of days
Why this matters
- Expected days 0.2 days / month
- Probability ~1% of days
- Intensity Up to ~97 (P95)
Low visibility proxy: same as fog-likely (RH ≥90% AND cloud ≥95%) — true visibility requires hourly visibility data is possible on ~0 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Frequently asked questions
Is September a good time to visit Johannesburg South?
Typical September days in Johannesburg South reach highs of 24°C (75°F) with nights around 9°C (48°F). It usually feels warm by day and cool after dark. Overall, September sits in the middle of the Johannesburg South climate range.
What are temperatures like in September?
In September, you can usually expect highs of 24°C (75°F) and lows near 9°C (48°F). That means warm days and cool nights, so pack layers you can add or remove.
How much does it rain in September?
Rainfall in September averages 20 mm (0.79 in) across roughly 5 days. Overall it is a mostly dry time of year, so showers are usually brief rather than all-day downpours.
How many hours of daylight are there in September?
You can expect about 12 hours of daylight in September. Sunrise is typically around 06:04 and sunset near 18:01. Daylight is fairly typical, with enough time for sightseeing.
How strong is the sun in September?
UV levels frequently reach very high levels (around 8), so strong sun protection is essential, especially around midday.
Is it windy in September?
In September, average wind speeds are around 13 km/h (8 mph), with gusts on the windiest days reaching about 57 km/h (35 mph). On the ground, it is it can feel quite windy at times, particularly when weather systems move through.