Free tools · Measured from space

Heat in Ward 12, City of Johannesburg

Summer 2025/26: the ground in Ward 12, City of Johannesburg reached about 38 °C on clear mornings. That is the ground (roofs, roads, soil), not the air. The 7th hottest of 13 summers since 2014. In summer the ground here reads +2.4 °C against its municipality’s average (since 2014).

Land surface temperature is how hot the ground itself is: roofs, roads, bare soil and leaves, as a satellite sees them from above. Landsat passes at about 10 in the morning and sees only through clear skies. It is not the air temperature a weather station gives: on a sunny day the ground is often 10 to 20 degrees hotter than the air, and hard, dark, dry surfaces heat up most while trees, grass and water stay cooler.

What it is not: not the afternoon peak, not the night, not the air you feel in the shade, and not a reading at any one house. A month with clouds rests on few clear looks.

Summer 2025/26

38.0 °CThe ground, not the airDecember to February, clear mornings
2015/16Hottest summer since 201440.8 °C; the coolest was 2021/22, 35.5 °C
+2.4 °CAgainst its municipalityThe ward’s summers against the municipality’s average, 13 summers since 2014

Every summer since 1987

Each summer (December to February, named by the year it ends) on clear mornings. Bars start at 27 °C, not zero. Darker: Landsat 8 and 9 (from 2014); lighter: Landsat 5 and 7. A gap is a summer seen too little.

Show the numbers

Land surface temperature each summer, 1987 to 2026: every figure
When or what	Figure
Summer 1986 to 87	33.5 °C
Summer 1990 to 91	34.1 °C
Summer 1991 to 92	38.6 °C
Summer 1995 to 96	29.7 °C
Summer 2000 to 01	34.1 °C
Summer 2001 to 02	36.7 °C
Summer 2002 to 03	32.6 °C
Summer 2011 to 12	37.5 °C
Summer 2012 to 13	35.0 °C
Summer 2013 to 14	37.1 °C
Summer 2014 to 15	37.5 °C
Summer 2015 to 16	40.8 °C
Summer 2016 to 17	38.8 °C
Summer 2017 to 18	36.4 °C
Summer 2018 to 19	39.2 °C
Summer 2019 to 20	38.8 °C
Summer 2020 to 21	37.3 °C
Summer 2021 to 22	35.5 °C
Summer 2022 to 23	36.3 °C
Summer 2023 to 24	40.4 °C
Summer 2024 to 25	40.1 °C
Summer 2025 to 26	38.0 °C

The shape of a year

Each month’s average since 2014, clear mornings. Bars start at 16 °C.

Show the numbers

Land surface temperature by calendar month, since 2014: every figure
When or what	Figure
January	38.4 °C
February	36.4 °C
March	33.5 °C
April	27.8 °C
May	23.1 °C
June	18.1 °C
July	18.2 °C
August	25.4 °C
September	33.1 °C
October	38.3 °C
November	39.1 °C
December	39.8 °C

Month by month

Month	Land surface temperature	Clear looks
October 2026	41.0 °C	3.7
September 2026	30.5 °C	1.9
August 2026	23.6 °C	4.0
July 2026	19.3 °C	3.7
June 2026	19.5 °C	2.7
May 2026	21.3 °C	3.3
April 2026	31.4 °C	0.3
March 2026	31.8 °C	1.5
February 2026	37.5 °C	2.4
January 2026	38.5 °C	3.7
December 2025	38.1 °C	1.0
November 2025	38.0 °C	2.2
October 2025	31.3 °C	0.9
September 2025	32.8 °C	2.8
August 2025	23.1 °C	4.2
July 2025	18.3 °C	1.8
June 2025	19.6 °C	1.7
May 2025	21.6 °C	4.0
April 2025	25.3 °C	2.1
March 2025	35.1 °C	0.7
February 2025	Seen too little	0.1
January 2025	37.2 °C	1.2
December 2024	43.0 °C	2.4
November 2024	42.7 °C	2.9

“Clear looks” is how many times the average 240 m patch of the place was seen through clear sky that month. Under one, part of the place was not seen at all, so the figure leans on the part that was.

City of Johannesburg and its wards · Every municipality, ranked

Source

Measured from space by the American Landsat satellites: the ground, not the air.

How we worked this out

Landsat 5 to 2011, Landsat 7 to bridge the gaps, Landsat 8 and 9 from 2013: different satellites pass at slightly different times, so compare summers within the same years first.

What we changed: we kept only the clear land cells (no cloud, cloud shadow, snow or water, with a margin round each cloud), read them at 480 m, and averaged them over each 2026 ward each month; larger places are the sums of their wards.

Landsat imagery courtesy of the U.S. Geological Survey (Landsat Collection 2 surface temperature, through Digital Earth Africa’s copy).

Dataset: land surface temperature by ward, release of 13 November 2026.