May Weather in Johannesburg, South Africa

Last updated: August 31, 2025

In May, Johannesburg experiences a delightful transition into winter, with maximum temperatures reaching 26°C (78°F) and cooler nights dropping to an average of 13°C (56°F). On the chillier side, temperatures can dip as low as -1°C (30°F), making warm layers a must for early mornings and late evenings. The city sees minimal rainfall, with just 13 mm (0.5 in) of precipitation on average, and only about one day of rain, allowing for plenty of sunshine amidst the mild weather. Humidity levels are relatively high at 82%, creating a crisp yet comfortable atmosphere perfect for outdoor activities. Embrace the vibrant urban life of Johannesburg this May as it seamlessly blends pleasant weather with captivating experiences.

May Temperature in Johannesburg

In May, Johannesburg experiences a noticeable transition into cooler weather, with temperatures typically ranging from a chilly -1°C (30°F) at night to a pleasant 26°C (78°F) during the day. This drop marks a significant shift from the warmer months, as the average temperature settles around 13°C (56°F), making it one of the cooler months of the year. As autumn takes hold, the contrast between the crisp morning air and the mild afternoon sun creates a unique climate, allowing residents and visitors to enjoy outdoor activities in more comfortable conditions. While much of the preceding months, particularly April and March, offered higher daytime highs, May’s weather encourages layering and a cozy embrace of the seasonal change.

May Weather in Johannesburg: Daily Temperature Highs, Lows, and Averages

The chart illustrates May temperature patterns in Johannesburg, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Johannesburg, May typically has an average temperature of {2}°C ({3}°F), with highs reaching up to {4}°C ({5}°F) and lows dropping to around {6}°C ({7}°F).
JanFebMarAprMayJunJulAugSepOctNovDec696866615651505763666868
Data source: Temperature data for Johannesburg generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

May Precipitation in Johannesburg

In May, Johannesburg transitions into the dry winter season, with precipitation dropping significantly to just 13 mm (0.5 in) over typically only one day of rain. This marks a stark contrast to the wetter months preceding it, where January and February record over 130 mm (5.1 in) and 138 mm (5.4 in), respectively. The trend of diminishing rainfall continues into June, further emphasizing May's position as a turning point for the city's climate. As the landscape shifts towards winter, residents can expect considerably drier days ahead, setting the stage for a season characterized by crisp air and bright, sunny skies.

May Precipitation Trends in Johannesburg

The chart displays monthly precipitation patterns in Johannesburg, with values for each month alongside May’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how May’s conditions compare to those of other months. In Johannesburg, May typically receives around {2} mm ({3} inches) of precipitation spread over approximately {4} days.
JanFebMarAprMayJunJulAugSepOctNovDec13013879631362396397146
Data source: Precipitation data for May generated using information from the Copernicus Climate Change Service.
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May Humidity in Johannesburg

As May arrives in Johannesburg, South Africa, residents experience a notable increase in humidity, reaching 82%. This marks a slight uptick from April’s 81%, showcasing the trend of increasing moisture as the city transitions into the winter months. Following this peak, humidity levels steadily decline, hitting a low of 71% in July before gradually rising again in November. Overall, the humidity in Johannesburg exhibits a seasonal oscillation, with elevated levels in early and late summer, while the winter months offer a refreshing reprieve from the sultry conditions.

May Average Humidity in Johannesburg

This chart illustrates the average monthly humidity levels in Johannesburg, with May’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In May, average humidity in Johannesburg is approximately {2}%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec79%77%77%81%83%73%71%68%74%74%82%81%
Data source: Humidity data for May generated using information from the Copernicus Climate Change Service.

May UV Index in Johannesburg

In May, Johannesburg experiences a notable shift in its sun intensity with a UV Index of 7, categorized as high. This month marks a decrease from the extreme levels seen in the early months of the year, offering a more forgiving burn time of 25 minutes compared to the perilous 10 minutes of January through March. As autumn sets in, the sun's rays become milder, allowing residents and visitors to enjoy the outdoors with a bit more safety; however, caution is still advised to prevent overexposure. Looking towards June and July, the UV Index remains steady at 6, maintaining the high exposure category, making it essential to stay informed and protected. For more detailed insights, check the Johannesburg UV Index.

Maximum UV Index Levels in Johannesburg for May

The chart shows the monthly maximum UV Index (UVI) for Johannesburg in May, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In May, the maximum UV index in Johannesburg typically reaches {2}, which falls under the {3} exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec15151310766811121416
Data source: Johannesburg May UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

  •  Extreme (11+): Avoid the sun, stay in shade.
  •  Very High (8-10): Limit sun exposure.
  •  High (6-7): Use SPF 30+ and protective clothing.
  •  Moderate (3-5): Midday shade recommended.
  •  Low (0-2): No protection needed.

May Sunshine in Johannesburg

As autumn transitions to winter in Johannesburg, May enjoys a generous 319 hours of sunshine, slightly outshining April’s 315 hours. This month marks the tail end of a brilliant autumn, where sunlight begins to wane but remains notably bright compared to the upcoming winter months. Throughout the year, sunshine in Johannesburg exhibits a clear upward trend from the dry summer months, peaking in October and November with 370 and 371 hours respectively. As the warm rays linger into May, residents can relish the vibrant outdoors before the chill of June sets in with its 298 hours of sunlight, hinting at the approaching winter. The sun in Johannesburg not only brightens the day but also serves as a reminder of the city's unique climate rhythms.

Monthly Sunshine Duration in Johannesburg: May Highlighted

The May sunshine duration represents the total number of hours Johannesburg experiences direct sunlight during the month of May, excluding cloudy or obstructed periods. This chart compares the sunshine duration of May with the other months of the year.
JanFebMarAprMayJunJulAugSepOctNovDec308h317h354h315h319h298h314h329h337h362h370h371h
Data source: Johannesburg May Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Johannesburg During May

In May, Johannesburg enjoys a high likelihood of sunny weather, boasting an impressive 80% chance of sunshine. This trend continues from April's peak, where residents revelled in 81% sunny days, subtly transitioning into the chillier months of June and July. Notably, June elevates the sunshine odds to 83%, setting the stage for even sunnier days ahead. This pattern illustrates a distinct shift, as the cooler winter months often bring clearer skies, making May an ideal time for outdoor activities before the winter sets in. Whether it's basking in the sun or enjoying the mild temperatures, May certainly holds its own in Johannesburg's vibrant climate calendar.

Percentage of Sunny Days in May in Johannesburg

The chart illustrates the percentage of sunny days in Johannesburg throughout the year, with May highlighted. It highlights the variation in sunshine across each month and provides an overview of the typical frequency of sunny days, offering insights into how often Johannesburg experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec29%33%67%81%80%83%95%80%78%61%60%41%
Data source: Johannesburg May chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Johannesburg in May

In Johannesburg, South Africa, daylight duration exhibits a fascinating seasonal rhythm that reflects the shifting months. Starting the year with an impressive 13 hours of daylight in January, the days gradually shorten, reaching 10 hours by May. This decrease in daylight marks the transition into winter, where durations remain steady at 10 hours through June and July. As winter wanes, daylight starts to extend again in August, culminating in a gentle resurgence to 12 hours by October. The cycle completes its journey as November and December once more bask in the longer days of 13 hours, heralding the return of summer. This annual ebb and flow of daylight beautifully encapsulates Johannesburg’s seasonal charm.

Average Daylight Hours in Johannesburg for May

The chart illustrates the variation in daylight duration in Johannesburg throughout the year, with May highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec13h 33m12h 57m12h 12m11h 26m10h 48m10h 30m10h 40m11h 12m11h 56m12h 42m13h 23m13h 44m
Data source: Johannesburg daylight hours, calculated by summing the hours between sunrise and sunset for each day.

May Winds in Johannesburg

In May, Johannesburg experiences a mild transition in wind patterns, with an average wind speed of 2.7 m/s (6 mph). This slight uptick from the preceding months underscores a gentle awakening of the winter winds in June, which see an increase to 2.9 m/s (6 mph). The trend reveals that the city's winds remain relatively calm compared to the breezier months ahead, like November, where speeds peak at 4.2 m/s (9 mph). Overall, May finds a middle ground—characterized by its soft breezes—preparing the city for the more robust winds that winter will bring.

Average May Wind Speed in Johannesburg

The chart displays monthly wind speed patterns in Johannesburg, with values for each month shown alongside May's data, which is highlighted for easy comparison. It illustrates the average wind speed, offering insights into how May's wind conditions compare to the rest of the year.
JanFebMarAprMayJunJulAugSepOctNovDec3.22.82.62.62.7 m/s2.92.93.93.73.74.23.3
Data source: Johannesburg May wind data, generated using information from the Copernicus Climate Change Service.

How May Weather in Johannesburg Compares to Other Months

Weather in Johannesburg varies notably across the year, with each month offering distinct climate conditions. This page compares May’s weather to other months in Johannesburg, focusing on differences in temperature, rainfall, humidity, and UV levels.

In comparing the weather in May and January, May tends to be much cooler and drier. With temperatures ranging from a minimum of -1°C (30°F) to a maximum of 26°C (78°F) and only about 13 mm (0.5 in) of precipitation over just one day, May usually offers a mild climate with an average temperature of 13°C (56°F) and higher humidity at 82%. In contrast, January is characterized by significantly warmer weather, with temperatures varying from a minimum of 9°C (48°F) to a high of 33°C (92°F), and it is much wetter, receiving around 130 mm (5.1 in) of rain over approximately 14 days. The average temperature in January sits at a comfortable 20°C (69°F). For more detailed insights, check out Johannesburg weather in January.

When comparing the weather in May and February, notable differences arise in temperature and precipitation. In May, temperatures range from a chilly minimum of -1°C (30°F) to a pleasant maximum of 26°C (78°F), with an average of 13°C (56°F). In contrast, February enjoys warmer conditions, with minimum temperatures of 10°C (51°F) and maximums reaching 31°C (87°F), averaging around 20°C (68°F). Furthermore, February experiences significantly higher rainfall, totaling 138 mm (5.4 in) over 16 days, compared to May's mild precipitation of just 13 mm (0.5 in) on a single day. Despite the warmer temperatures in February, the humidity is relatively close, with May at 82% and February at 77%. For more details, check out Johannesburg weather in February.

In comparing the weather between May and March, notable differences emerge. May typically experiences cooler temperatures, ranging from a minimum of -1°C (30°F) to an average of 13°C (56°F) and reaching a maximum of 26°C (78°F), along with relatively low precipitation of just 13 mm (0.5 in) over only one day, and humidity levels at 82%. In contrast, March sees milder temperatures, with a minimum of 8°C (46°F), an average of 19°C (66°F), and a maximum of 30°C (86°F). However, it also experiences significantly higher precipitation, totaling 79 mm (3.1 in) over about ten days, and slightly lower humidity at 77%. For more detailed information, you can visit Johannesburg weather in March.

In comparing the weather of April and May, April experiences generally warmer temperatures with a minimum of 3°C (38°F), an average of 16°C (61°F), and a maximum of 29°C (85°F). In contrast, May sees cooler temperatures, with a minimum of -1°C (30°F) and an average of 13°C (56°F), reaching a maximum of 26°C (78°F). Additionally, April has significantly higher precipitation, totaling 63 mm (2.5 in) over 10 days, compared to May's much lower 13 mm (0.5 in) over just 1 day. Humidity levels remain relatively similar, with April at 81% and May slightly higher at 82%. For more details about the weather in April, you can visit Johannesburg weather in April.

May and June present distinct weather characteristics. In May, temperatures range from a minimum of -1°C (30°F) to a maximum of 26°C (78°F), with an average of 13°C (56°F). The month experiences relatively high humidity at 82% and a slight amount of precipitation, totaling 13 mm (0.5 in) over just one day. In contrast, June sees a minimum temperature drop to -4°C (24°F) and a maximum of 24°C (76°F), with an average temperature of 11°C (51°F). Precipitation decreases to 6 mm (0.2 in), also occurring on only one day, and humidity lowers to 73%. For a more detailed look at June weather specifics, you can check out Johannesburg weather in June.

In May, Johannesburg experiences a wider temperature range, with minimal temperatures dipping to -1°C (30°F) and average highs reaching 26°C (78°F), while July features lower minimum temperatures of -4°C (25°F) but similar maximums, capping at 25°C (78°F). Precipitation also differs notably; May receives 13 mm (0.5 in) over just one day, while July enjoys drier conditions with only 2 mm (0.1 in) and no rainy days. Humidity levels are higher in May at 82%, compared to 71% in July, contributing to a more comfortable feel in the mid-winter month. For more insights, you can check Johannesburg weather in July.

May and August exhibit distinct differences in weather patterns. In May, temperatures range from a minimum of -1°C (30°F) to a maximum of 26°C (78°F), with an average of 13°C (56°F). This month experiences relatively high humidity at 82% and some light precipitation, totaling 13 mm over just one day. In contrast, August enjoys slightly warmer weather, with temperatures ranging from -1°C (30°F) to 27°C (80°F) and an average temperature of 14°C (57°F). Notably, August is drier, with only 3 mm of precipitation over the course of the month and humidity dropping to 68%. For more specific insights into weather patterns, you can check Johannesburg weather in August.

May and September exhibit distinct weather patterns, reflecting the transition from late spring to early autumn. In May, temperatures range from a chilly minimum of -1°C (30°F) to a pleasant maximum of 26°C (78°F), with an average temperature of 13°C (56°F). The month typically sees about 13 mm (0.5 in) of precipitation over just one day and maintains high humidity at 82%. In contrast, September features milder temperatures, with a minimum of -1°C (31°F) and a maximum reaching 32°C (91°F), averaging 17°C (64°F). Additionally, September experiences lower precipitation at 8 mm (0.3 in) over two days and a decrease in humidity to 74%. For a detailed look at September weather, you can visit Johannesburg weather in September.

When comparing the weather in May and October, there are notable differences in temperature and precipitation. May typically has a wider range of temperatures, with minimums dropping to 1°C (30°F) and maximums reaching up to 26°C (78°F), while October experiences milder nights with a minimum of 4°C (40°F) and maximums that can soar to 33°C (92°F). Additionally, May sees minimal precipitation, averaging just 13 mm (0.5 in) over only 1 day, compared to October, which receives significantly more rain at 63 mm (2.5 in) across 8 days. Humidity levels are slightly higher in May at 82%, while October's humidity is more comfortable at 74%. For those interested in more details about October weather, you can check Johannesburg weather in October.

May and November present contrasting weather characteristics. In May, temperatures range from a chilly minimum of -1°C (30°F) to a pleasant maximum of 26°C (78°F), with an average of 13°C (56°F). The month sees very little precipitation, averaging only 13 mm (0.5 in) over about a day, making it relatively dry, with humidity sitting at 82%.

In stark contrast, November boasts much warmer temperatures, with a minimum of 4°C (40°F) and a maximum reaching up to 34°C (93°F), resulting in a higher average of 20°C (68°F). However, November is also far wetter, with precipitation totaling 97 mm (3.8 in) over 13 days, while maintaining the same humidity level of 82%. For a more detailed look at November's weather, check out Johannesburg weather in November.

In Johannesburg, May and December showcase stark contrasts in weather patterns. May typically experiences cooler temperatures, with a range from a chilly minimum of -1°C (30°F) to an average of 13°C (56°F) and a warm maximum of 26°C (78°F). It's relatively dry, receiving only 13 mm (0.5 in) of precipitation across just one day, while humidity remains high at 82%.

In contrast, December brings a warmer climate, with temperatures ranging from a minimum of 10°C (50°F) to a sunny average of 20°C (69°F) and peaks at a hot 34°C (93°F). This month is notably wetter, with 146 mm (5.7 in) of rain spread over 19 days, and humidity levels remain similar at 81%. For further insights into December's weather in Johannesburg, visit Johannesburg weather in December.

Compare Johannesburg's Climate with Cities Worldwide

Conclusion: What to Expect From May Weather in Johannesburg

As May arrives in Johannesburg, the weather showcases a delightful transition into the cooler months. With pleasant daytime temperatures peaking around 26°C (78°F), the city offers a comfortable escape from the heat of summer. Nights can be quite chilly, dipping to an average of 13°C (56°F), offering a refreshing contrast. Unlike the previous months, May enjoys significantly lower precipitation, with only 13 mm (0.5 in) of rainfall on just one day, making it an ideal time for outdoor activities. The humidity also remains palpable at 82%, creating a crisp yet vibrant atmosphere. For a deeper dive into how this charming city’s climate evolves throughout the year, check out Johannesburg Climate.