In Chennai the hottest afternoons and the warmest nights do not arrive together with the stickiest air. Across the twelve months from June 2022 to May 2023, Nungambakkam’s average daily high peaked at 37.1°C in June, its nights were warmest in May at 28.5°C, and its mornings were most humid in November and December, at 87%.
That is the year we have drawn as a circle below, using the monthly table the Regional Meteorological Centre supplies to the state’s Statistical Hand Book 2022-23. It is the latest year the Tamil Nadu government has published. Each bar is one month’s average afternoon high.
- Each wedge is one month’s mean maximum temperature at Nungambakkam, starting with June 2022 at the top and running clockwise to May 2023.
- Orange wedges are the three months whose average high reached 35°C or more: April, May and June.
- Bars are drawn from zero, so a gap of a few degrees looks modest. In Chennai, a 7.8°C swing between June and November is the difference between a punishing and a pleasant afternoon.
Days and nights move together, but not evenly
The coolest afternoons came in November 2022, at an average of 29.3°C, in the middle of the northeast monsoon season. The coolest nights came later, in January and February 2023, at 22.1°C and 22.0°C. The two lines rise and fall together, but the gap between them changes.
That gap, the daily range, was widest in June 2022 at 9.2°C, as afternoons stayed hot while nights stayed warm. It was narrowest in December 2022 at 5.8°C, in the wet, cloudy end of the year, when afternoons were mildest.
The smallest gap between the average day and night temperature at Nungambakkam in the year, recorded in December 2022, against 9.2°C in June (Statistical Hand Book 2022-23, Table 3.1).
Humidity tells the other half of the story
The same IMD table records relative humidity twice a day, at 8.30 am and 5.30 pm. Mornings are always damper. At Nungambakkam the morning reading never fell below 72% all year, and it reached 87% in November and December. Evening air was driest in February 2023, at 62%.
The airport station at Meenambakkam, further from the sea, is drier in the evenings, with readings as low as 53% in February 2023. It is also hotter by day in late summer. Its average high in May 2023 was 37.8°C, 1.1°C above Nungambakkam, and 2.3°C above in February. Its nights were cooler in every month of the year, by between 0.4°C and 1.2°C.
Was this a typical year?
In the same handbook series, the 2020-21 edition shows Nungambakkam averaging 39.0°C by day and 29.7°C by night in June 2019, about 2°C hotter than June 2022. The WMO normals for Meenambakkam, published by Japan’s Tokyo Climate Center, give May the highest mean temperature, 33.0°C, and January the lowest, 25.4°C. That matches the circle’s shape.
The numbers behind the graphic
| Month | Nungambakkam mean max (°C) | Nungambakkam mean min (°C) | Nungambakkam humidity 8.30 am (%) | Nungambakkam humidity 5.30 pm (%) | Meenambakkam mean max (°C) | Meenambakkam mean min (°C) | Meenambakkam humidity 8.30 am (%) | Meenambakkam humidity 5.30 pm (%) |
|---|---|---|---|---|---|---|---|---|
| Jun 2022 | 37.1 | 27.9 | 72 | 69 | 37.3 | 27.0 | 67 | 60 |
| Jul 2022 | 34.5 | 26.9 | 75 | 68 | 34.4 | 25.8 | 76 | 65 |
| Aug 2022 | 34.9 | 27.0 | 73 | 65 | 35.0 | 25.8 | 72 | 62 |
| Sep 2022 | 34.3 | 27.1 | 73 | 71 | 34.3 | 26.0 | 76 | 67 |
| Oct 2022 | 32.2 | 25.2 | 81 | 71 | 32.3 | 24.2 | 82 | 70 |
| Nov 2022 | 29.3 | 23.4 | 87 | 80 | 29.4 | 23.0 | 87 | 77 |
| Dec 2022 | 29.6 | 23.8 | 87 | 77 | 29.7 | 23.1 | 89 | 74 |
| Jan 2023 | 29.9 | 22.1 | 82 | 65 | 30.3 | 21.2 | 82 | 59 |
| Feb 2023 | 30.2 | 22.0 | 82 | 62 | 32.5 | 21.5 | 80 | 53 |
| Mar 2023 | 32.6 | 24.9 | 79 | 67 | 33.4 | 23.8 | 78 | 62 |
| Apr 2023 | 35.0 | 27.2 | 73 | 66 | 36.3 | 26.4 | 75 | 62 |
| May 2023 | 36.7 | 28.5 | 72 | 67 | 37.8 | 27.8 | 70 | 64 |
Source: Regional Meteorological Centre, Chennai, as published in the Statistical Hand Book of Tamil Nadu 2022-23, Table 3.1, Temperature at Select Stations in Tamil Nadu 2022-23 (Department of Economics and Statistics). Observed monthly means for June 2022 to May 2023.
About the data
These are observed monthly averages for one year, June 2022 to May 2023, not 30-year normals. Each mean maximum is the average of that month’s daily highs, and each mean minimum the average of its daily lows. Humidity is the monthly average of readings taken at 8.30 am and 5.30 pm. Nungambakkam is near the coast; Meenambakkam is at the airport, inland.
The state handbook does not print IMD’s 1991-2020 normals, and IMD’s own station tables could not be opened for this piece, so we have not shown them. Rainy days and heat index are not included, and two stations cannot show how neighbourhoods differ.
Quick answers
What is the hottest month in Chennai?
In the 2022-23 data, June had the highest average daily high at Nungambakkam (37.1°C) and May had the warmest nights (28.5°C). At Meenambakkam, May was hottest by day at 37.8°C.
When is Chennai most humid?
Mornings in November and December, when the 8.30 am reading averaged 87% at Nungambakkam in 2022, and 87% to 89% at Meenambakkam.
Information checked against official sources on 21 October 2026. Figures can be revised; confirm on the linked official pages before relying on them.
Sources
- Statistical Hand Book of Tamil Nadu 2022-23, Chapter 3: Climate and Rainfall, Table 3.1 (Department of Economics and Statistics, Government of Tamil Nadu; data from the Regional Meteorological Centre, Chennai)
- Statistical Hand Book of Tamil Nadu 2020-21, Chapter 3: Climate and Rainfall, Table 3.1 (Department of Economics and Statistics, Government of Tamil Nadu)
- Monthly climate normals, Chennai/Minambakkam station 43279 (Tokyo Climate Center, Japan Meteorological Agency, WMO data)
