Johannesburg WBGT Today — Wet Bulb Globe Temperature
Updated planning preview · 5:00 forecast from WeatherAPI
Estimated WBGT
11.3°C
Low
Typical activity may proceed with routine hydration.
Temperature
17°C
Humidity
36%
Heat index
17°C
UV index
0.0
Best outdoor window
17:00–10:00
Lowest combined heat and UV load in the available hourly preview.
Hourly WBGT
WBGT values are labeled as modeled estimates until a provider supplies measured readings.
| Time | Temperature | Heat index | Estimated WBGT | UV | Risk |
|---|---|---|---|---|---|
| 07 | 17°C | 17°C | 13.3°C | 0.3 | Low |
| 09 | 20°C | 20°C | 15.1°C | 3.4 | Low |
| 11 | 22°C | 23°C | 16.7°C | 8.4 | Low |
| 13 | 24°C | 23°C | 17.5°C | 8.7 | Low |
| 15 | 25°C | 24°C | 17.8°C | 4.1 | Low |
| 17 | 25°C | 24°C | 17.6°C | 0.5 | Low |
| 08 | 17°C | 17°C | 14.6°C | 1.4 | Low |
| 10 | 21°C | 21°C | 16.4°C | 6.1 | Low |
Today's outlook
In Johannesburg, the highest modeled heat burden in this preview occurs around 10:00. The recommended window is selected from the lowest combined risk score, temperature, and UV—not from generic city copy.
Three-day forecast
Sunday
Heat index up to 24°C
25°C / 16°C
LowMonday
Heat index up to 24°C
24°C / 13°C
LowTuesday
Heat index up to 24°C
22°C / 13°C
LowToday in Johannesburg
What changes across the day
Based on the available hourly WeatherAPI forecast
Peak heat index
24°C at 15:00
The preview low is 17°C around 7:00.
Feels-like difference
Matches air temp
Current humidity is 36%, one input that changes evaporative cooling.
Peak UV
8.7 at 13:00
UV and heat are separate hazards; the lowest-heat hour may still need sun protection.
Tomorrow's direction
about steady tomorrow
Today's forecast range is 16°C–25°C.
Where these numbers come from
WeatherAPI supplies the forecast. HeatGuard calculates heat-index risk and models WBGT from forecast temperature, humidity and a daytime solar allowance. Modeled WBGT is not an on-site globe-thermometer reading.
Local planning context
Planning for heat in Johannesburg, South Africa
Johannesburg's elevation, strong sun and outdoor-work exposure can create heat stress even when humidity is comparatively lower. South African urban-heat guidance uses WBGT while emphasizing that the index is distinct from ordinary air temperature.
Forecasts describe outdoor conditions, not an individual's medical risk. Workload, duration, shade, clothing, acclimatization and health can change the appropriate decision.
Check South African Cities Support Programme urban-heat guidance ↗Keep planning
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