Chennai weather forecast: Moderate rainy, high humidity; AQI remains moderate

Chennai is scheduled to begin Monday, January 26, 2026, with moderate rain and a sticky, humid atmosphere throughout the day. The forecast indicates an 81% chance of rain, with temperatures reaching a high of 27.9°C and humidity at 77%. This follows yesterday's "moderate" air quality, which registered an AQI-IN of 75, primarily due to particulate pollutants. Residents are advised to prepare for wet conditions and potential air quality irritation, while the city anticipates a shift to sunny skies and clearer weather from January 27 through February 1.

Today's Detailed Forecast (January 26)

The day's forecast includes a high of 27.9°C and a low of 23.3°C, resulting in an average temperature near 25°C. This temperature range is considered comfortably warm, avoiding scorching conditions.
Humidity is projected to remain elevated at approximately 77%. This high humidity level can make even short walks feel muggy once any rain eases.
Winds are expected to pick up at times, with speeds reaching 24.1 kmph. These wind bursts may offer brief periods of relief between showers, but they also increase the likelihood of getting drenched if rain becomes breezy.
Rain is a significant factor for today, with Chennai having an 81% chance of precipitation. The total rainfall for the day could accumulate to around 11 mm.
Occasional dips in visibility are anticipated during heavier rain spells. The average visibility is estimated at about 9.8 km.
These visibility reductions are particularly likely if showers coincide with peak traffic hours. While specific hour-by-hour timing is not provided, a "moderate rain" day in coastal Chennai typically plays out in pulses.
"pulses—showers that come and go rather than all-day continuous rainfall"
It is advisable to plan errands within flexible time windows due to this intermittent rain pattern. Sunrise occurred at 6:36 AM, and sunset is expected at 6:08 PM.
The evening commute may therefore take place under fading light and on wet roads.

Air Quality Update

Yesterday’s air quality, on Sunday, January 25, was categorized as "moderate." Chennai’s air quality index registered AQI-IN 75.
On the US scale, the reading was AQI-US 117. This US scale reading also indicates air that is not considered.
"clean" for everyone—especially sensitive groups.
The primary contributors to this air quality were particulate pollutants. PM2.5 levels were recorded at 44, and PM10 levels were at 53.
Carbon monoxide (CO) was also present at a level of 366.
For many individuals, "moderate" air quality is manageable. However, it can still trigger symptoms such as scratchy throats, mild headaches, or wheezing.
This is particularly true for children, older adults, and people with respiratory conditions, especially near traffic-heavy junctions. Today’s rain may contribute to knocking down some airborne particles.
This could offer short-lived relief from pollution. Conversely, high humidity can sometimes make the air feel heavier.
If winds calm between showers, pollution may linger locally. The weather could improve air quality in spells, but a consistently fresh atmosphere throughout the day should not be assumed.

Recommendations for Today

Keeping a day kit simple is recommended for today. An umbrella or rain jacket is considered non-negotiable.
Non-slip footwear will be beneficial on waterlogged patches. Those commuting by two-wheeler should allow extra time for their journeys.
Moderate rain frequently causes sudden slowdowns and slick turns on roads. For fitness activities, choosing a lighter workout indoors is suggested.
Alternatively, a short walk during a lull in the rain could be an option. Individuals sensitive to pollution should consider avoiding main-road stretches.
PM2.5 exposure can spike in these areas, even on rainy days. Hydrating well is important, as humidity can lead to sweating without immediate awareness.

Outlook for the Week Ahead

Following today’s showers, Chennai is expected to transition to a "quick shift to sunshine and steadier skies." From January 27 through February 1, the forecast indicates sunny skies each day.
Zero millimeters of rain are expected during this period. Daytime highs are projected to remain steady, ranging from 28°C to 28.6°C.
Nights will gradually cool, reaching the week’s lowest temperature of approximately 20.8°C on January 30. Winds are anticipated to remain moderate, generally between 17 and 19 kmph.
Humidity levels will ease compared to today, hovering in the upper 60s. For those planning outdoor activities, Tuesday, January 27, and Wednesday, January 28, appear to be the "cleanest, easiest days."
These days offer sunny skies, manageable warmth, and no rain interruptions. Today, January 26, requires caution for travel and road safety due to the wet conditions.
A small skywatcher’s note indicates that the moon is heading toward a Full Moon on February 1. This often results in brighter late-evening skies for those who are out after sunset.
This will be especially noticeable once the clouds clear later in the week.
Data referenced in this article is taken from AQI.in.
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