Hottest (avg)
#10 / 12
On the cooler side.
May in context
How it compares to the rest of the year in Johannesburg South.
Wettest (avg)
#9 / 12
Typical rainfall for the year.
Daylight Hours
#10 / 12
Shorter days.
Windiest (avg)
#9 / 12
Close to the yearly wind average.
Highest UV
#10 / 12
UV is gentler than usual.
Most Humid
#7 / 12
Humidity stays close to the yearly norm.
Monthly climate breakdown
A detailed look at the typical climate conditions for May.
Thermal profile
Temperature
Typical daytime high
- Nighttime low
-
- Feels like (avg)
-
Light window
Sunshine
10.8 h
Average daylight
- UV index (max)
- 6
- Typical sun hours
- 06:39 - 17:29
Wet-day pattern
Rain & Snow
Typical rainfall
- Rainy days
- 4 days
- Cloud cover (avg)
- 22%
Air feel
Humidity & Wind
58%
Average humidity
- Wind (avg)
-
- Wind (max gusts)
-
Historical daily baseline
Daily climate explorer
Pick a day to inspect the usual conditions through May in Johannesburg South. Based on a 30-year historical climate baseline, not a forecast.
Primary control
Select a day
Scroll to compare daily conditions. The summary updates with your selection.
Secondary context
Monthly trend
Median daytime highs across the month, with a softer low line.
Median temperatureMedian lowTypical range
Day 15 selected for May. Temperature 18.7°C.
Historical disruption baseline
Typical disruptions in May
Based on 30 years of historical data, these are the disruption patterns most likely to affect plans in May.
Cold High impact
Cold feels-like nights Measures: Cold feels-like nights (min <=5C). Observed about 69% of days (21.3 days/month) in May. Historical risk signal only, not a day-by-day forecast.
Likely frequency
21.3 days / month
- Share of days
- ~69% of days
- Upper edge
- Up to ~5°C (P95)
Why this matters
Cold feels-like nights are possible on ~21 days. Long outdoor blocks become harder to sustain, so layer up and keep a warm indoor fallback nearby.
Rain High impact
Washout risk Measures: Washout day risk. Observed about 3% of days (1.0 days/month) in May. Historical risk signal only, not a day-by-day forecast.
Likely frequency
1.0 days / month
- Share of days
- ~3% of days
- Upper edge
- Up to ~19mm (P95)
Why this matters
Washout conditions are possible on ~1 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Rain Moderate
Rain disruption Measures: Likely rain disruption days. Observed about 3% of days (1.1 days/month) in May. Historical risk signal only, not a day-by-day forecast.
Likely frequency
1.1 days / month
- Share of days
- ~3% of days
- Upper edge
- Up to ~18mm (P95)
Why this matters
Rain disruption risk appears on ~1 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Cold Minor
Freezing nights Measures: Freezing nights (min <=0C). Observed about 2% of days (0.7 days/month) in May. Historical risk signal only, not a day-by-day forecast.
Likely frequency
0.7 days / month
- Share of days
- ~2% of days
- Upper edge
- Up to ~0°C (P95)
Why this matters
Freezing nights are possible on ~1 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Show all disruptions (15 more)
Rain High impact
Heavy rain days Measures: Heavy rain days (>=10mm). Observed about 1% of days (0.4 days/month) in May. Historical risk signal only, not a day-by-day forecast.
Likely frequency
0.4 days / month
- Share of days
- ~1% of days
- Upper edge
- Up to ~33mm (P95)
Why this matters
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
Strong gusts Measures: Strong gust days (>=60 km/h). Observed about 1% of days (0.2 days/month) in May. Historical risk signal only, not a day-by-day forecast.
Likely frequency
0.2 days / month
- Share of days
- ~1% of days
- Upper edge
- Up to ~72km/h (P95)
Why this matters
Strong gusts 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 May. Historical risk signal only, not a day-by-day forecast.
Likely frequency
0.2 days / month
- Share of days
- —
- Upper edge
- Up to ~19mm (P95)
Why this matters
Multi-day washout runs are 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 May. Historical risk signal only, not a day-by-day forecast.
Likely frequency
0.2 days / month
- Share of days
- ~1% of days
- Upper edge
- Up to ~62km/h (P95)
Why this matters
Stormy conditions are possible on ~0 days. Exposed activities and transport links are more likely to be disrupted, so keep sheltered alternatives ready.
Cold Minor
Cold nights Measures: Cold nights (min <=5C). Observed about 29% of days (8.9 days/month) in May. Historical risk signal only, not a day-by-day forecast.
Likely frequency
8.9 days / month
- Share of days
- ~29% of days
- Upper edge
- Up to ~5°C (P95)
Why this matters
Cold nights are possible on ~9 days. Long outdoor blocks become harder to sustain, so layer up and keep a warm indoor fallback nearby.
Rain Minor
Wet days Measures: Wet days (>=0.1mm). Observed about 19% of days (5.8 days/month) in May. Historical risk signal only, not a day-by-day forecast.
Likely frequency
5.8 days / month
- Share of days
- ~19% of days
- Upper edge
- Up to ~12mm (P95)
Why this matters
Measurable rain is possible on ~6 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Wind Minor
Gusty days Measures: Gusty days (>=40 km/h). Observed about 18% of days (5.5 days/month) in May. Historical risk signal only, not a day-by-day forecast.
Likely frequency
5.5 days / month
- Share of days
- ~18% of days
- Upper edge
- Up to ~59km/h (P95)
Why this matters
Gusty conditions are possible on ~5 days. Exposed activities and transport links are more likely to be disrupted, so keep sheltered alternatives ready.
Rain Minor
Rainy hours Measures: Rain-hours signal (>=3h rain). Observed about 12% of days (3.6 days/month) in May. Historical risk signal only, not a day-by-day forecast.
Likely frequency
3.6 days / month
- Share of days
- ~12% of days
- Upper edge
- Up to ~19h (P95)
Why this matters
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 11% of days (3.3 days/month) in May. Historical risk signal only, not a day-by-day forecast.
Likely frequency
3.3 days / month
- Share of days
- ~11% of days
- Upper edge
- Up to ~97% (P95)
Why this matters
Cloudy skies are possible on ~3 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 7% of days (2.3 days/month) in May. Historical risk signal only, not a day-by-day forecast.
Likely frequency
2.3 days / month
- Share of days
- ~7% of days
- Upper edge
- Up to ~92% (P95)
Why this matters
High humidity is possible on ~2 days. Comfort and pace can drop quickly, so plan shorter outdoor blocks with air-conditioned backup stops.
Rain Minor
Wet most of day Measures: Wet-most-of-day signal (>=6h rain). Observed about 7% of days (2.1 days/month) in May. Historical risk signal only, not a day-by-day forecast.
Likely frequency
2.1 days / month
- Share of days
- ~7% of days
- Upper edge
- Up to ~22h (P95)
Why this matters
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 4% of days (1.2 days/month) in May. Historical risk signal only, not a day-by-day forecast.
Likely frequency
1.2 days / month
- Share of days
- ~4% of days
- Upper edge
- Up to ~100% (P95)
Why this matters
Mostly cloudy skies are possible on ~1 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Cloud Minor
Overcast days Measures: Overcast days (cloud cover >=95%). Observed about 1% of days (0.4 days/month) in May. Historical risk signal only, not a day-by-day forecast.
Likely frequency
0.4 days / month
- Share of days
- ~1% of days
- Upper edge
- Up to ~100% (P95)
Why this matters
Overcast skies are possible on ~0 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Cold Minor
Cold days Measures: Cold days (max <=10C). Observed about 1% of days (0.3 days/month) in May. Historical risk signal only, not a day-by-day forecast.
Likely frequency
0.3 days / month
- Share of days
- ~1% of days
- Upper edge
- Up to ~10°C (P95)
Why this matters
Cold daytime conditions are possible on ~0 days. Long outdoor blocks become harder to sustain, so layer up and keep a warm indoor fallback nearby.
Cold Minor
Hard freeze nights Measures: Hard freeze nights (min <=-2C). Observed about 1% of days (0.2 days/month) in May. Historical risk signal only, not a day-by-day forecast.
Likely frequency
0.2 days / month
- Share of days
- ~1% of days
- Upper edge
- Up to ~-2°C (P95)
Why this matters
Hard freeze conditions are possible on ~0 days. Long outdoor blocks become harder to sustain, so layer up and keep a warm indoor fallback nearby.
Travel planning FAQ
Frequently asked questions
Quick answers to the weather questions you ask the most.
Is May a good time to visit Johannesburg South?
Typical May days in Johannesburg South reach highs of 19°C (66°F) with nights around 6°C (43°F). It usually feels mild by day and cold after dark. Overall, May sits in the middle of the Johannesburg South climate range.
What are temperatures like in May?
In May, you can usually expect highs of 19°C (66°F) and lows near 6°C (43°F). That means mild days and cold nights, so pack layers you can add or remove.
How much does it rain in May?
Rainfall in May averages 18 mm (0.71 in) across roughly 4 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 May?
You can expect about 11 hours of daylight in May. Sunrise is typically around 06:39 and sunset near 17:29. Days are on the shorter side, so plan activities around limited daylight.
How strong is the sun in May?
UV levels are often high (around 6). Regular sunscreen and a hat are recommended.
Is it windy in May?
In May, average wind speeds are around 10 km/h (6 mph), with gusts on the windiest days reaching about 45 km/h (28 mph). On the ground, it is it often feels breezy, especially in more exposed spots or along the coast.