Ooty — Seasonal Pollution Patterns
Month-by-month air quality patterns for Ooty across 3 years of CPCB data. Based on CPCB station data, 2016–present.
Tamil Nadu · Live Ooty AQI →
At a glance
Based on 3 years of CPCB monitoring across 1 stations, Ooty averages AQI 59 annually, with a pronounced seasonal pattern classified as flat year-round. The worst month is May at AQI 83 (Satisfactory) and the cleanest is July at AQI 47 (Good) — a 36-point swing between them. Severe days (AQI > 400) make up 0% of the record while Good-or-Satisfactory days account for 94.2%.
The four seasons
Indian meteorological seasons: Winter (Dec–Feb), Summer (Mar–May), Monsoon (Jun–Sep), Post-monsoon (Oct–Nov).
Winter
AQI 63Summer
AQI 71Monsoon
AQI 50Post-monsoon
AQI 55Climograph — monthly averages and Poor+ days
Bars show the long-run AQI average per month. The overlay line counts days in Poor, Very Poor or Severe bands.
Year × month heatmap
One cell per year-month combination.
Each cell = monthly average AQI for that year-month combination. Row averages on the right, column averages at the bottom.
| Year | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Avg |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2022 | — | — | — | — | — | — | — | 56 | 53 | 56 | 61 | 63 | 58 |
| 2023 | 64 | 73 | 69 | 71 | 91 | 61 | 51 | 59 | 30 | 56 | 32 | 40 | 59 |
| 2024 | 68 | 47 | 62 | 53 | 70 | 45 | 38 | 37 | 60 | 56 | 62 | 88 | 59 |
| Avg | 66 | 62 | 66 | 64 | 83 | 56 | 48 | 50 | 47 | 56 | 53 | 60 | — |
Winter in Ooty
Winter (Dec–Jan–Feb) in Ooty averages AQI 63 across 147 measured days — Satisfactory on the NAQI scale. 0% of those days fall in Very Poor or Severe; 93.9% are Good or Satisfactory. Year-on-year, winter worsened by 12.8% in the most recent comparison. Winter in Ooty is not the headline season, but shallow morning inversions can still produce short spikes. Ooty's cleanest months lie elsewhere in the calendar, so the winter response is less about evacuation than about protecting sensitive groups on the worst individual days.
Diwali, stubble burning and the monsoon
Three India-specific signatures that shape the seasonal curve.
Diwali week impact
The 7-day window around Diwali averages AQI 61 (Satisfactory), versus 53 (Satisfactory) for the rest of October. 18 sampled days across the CPCB record.
Stubble-burning window (Oct 15 – Nov 15)
In-window severe-day share 0% vs 0% outside the window. The difference is a direct signal of upwind crop-residue transport.
Monsoon cleansing (Jul 15 – Sep 15)
Core monsoon window averages AQI 46 (Good), compared with an annual mean of 59.
Summer
Summer (Mar–Apr–May) in Ooty averages AQI 71 across 131 measured days — Satisfactory on the NAQI scale. 0% of those days fall in Very Poor or Severe; 86.3% are Good or Satisfactory. Year-on-year, summer improved by 20.2% in the most recent comparison. Summer air in Ooty is shaped by a very different mix of forces. Rising temperatures drive deeper vertical mixing which dilutes local emissions, but pre-monsoon dust storms, wildfires and heat-accelerated ozone formation can all push AQI higher on individual days. Ooty's summer mean of 71 is the lighter side of the year for outdoor activity, though hot afternoons can still irritate sensitive airways.
Monsoon
Monsoon (Jun–Jul–Aug–Sep) in Ooty averages AQI 50 across 189 measured days — Good on the NAQI scale. 0% of those days fall in Very Poor or Severe; 96.8% are Good or Satisfactory. Year-on-year, monsoon improved by 2% in the most recent comparison. The Jul 15 – Sep 15 core monsoon window averages AQI 46, a 22% improvement on the annual mean of 59. Rain scrubs particulates out by wet deposition, and the deeper monsoon boundary layer disperses what remains vertically. Short-lived rebounds can happen between spells of rain, but the overall pattern is strongly favourable for outdoor activity. For anyone with asthma or heart conditions, monsoon is the easy-breathing stretch of the year in Ooty.
Post-monsoon
Post-monsoon (Oct–Nov) in Ooty averages AQI 55 across 140 measured days — Satisfactory on the NAQI scale. 0% of those days fall in Very Poor or Severe; 98.6% are Good or Satisfactory. Year-on-year, post-monsoon worsened by 28.4% in the most recent comparison. Post-monsoon in Ooty is the handoff from clean monsoon air to the winter peak, and the transition is rarely gentle.
Month-by-month trajectories
How each month has moved across the 3-year CPCB record.
First year vs latest year
Annual and per-season comparison.
Across the 3-year CPCB record Ooty is roughly stable overall — AQI moved from 58 in 2022 to 58 in 2024, a +0% change. No month shows a material worsening of 10% or more. No month shows a material improvement of 10% or more. Because Ooty's seasonal shape is flat year-round, policy action that targets the May peak buys disproportionate relief — most city-wide annual averages are dragged upwards by the worst two or three months.
Daily calendar heatmap
Every measured day for the last 3 years. Expand for the full 3-year archive.
Month-by-month deep dive
Tap any month to expand.
Jan2023–2024Latest AQI 68+6%
Jan in Ooty averages AQI 68 (Satisfactory) in the most recent year, having moved from 64 in 2023. Direction: stable (+6.3%).
Feb2023–2024Latest AQI 47-36%
Feb in Ooty averages AQI 47 (Good) in the most recent year, having moved from 73 in 2023. Direction: improving (-35.6%).
Mar2023–2024Latest AQI 62-10%
Mar in Ooty averages AQI 62 (Satisfactory) in the most recent year, having moved from 69 in 2023. Direction: improving (-10.1%).
Apr2023–2024Latest AQI 53-25%
Apr in Ooty averages AQI 53 (Satisfactory) in the most recent year, having moved from 71 in 2023. Direction: improving (-25.4%).
May2023–2024Latest AQI 70-23%
May in Ooty averages AQI 70 (Satisfactory) in the most recent year, having moved from 91 in 2023. Direction: improving (-23.1%).
Jun2023–2024Latest AQI 45-26%
Jun in Ooty averages AQI 45 (Good) in the most recent year, having moved from 61 in 2023. Direction: improving (-26.2%).
Jul2023–2024Latest AQI 38-26%
Jul in Ooty averages AQI 38 (Good) in the most recent year, having moved from 51 in 2023. Direction: improving (-25.5%).
Aug2022–2024Latest AQI 37-34%
Aug in Ooty averages AQI 37 (Good) in the most recent year, having moved from 56 in 2022. Direction: improving (-33.9%).
Sep2022–2024Latest AQI 60+13%
Sep in Ooty averages AQI 60 (Satisfactory) in the most recent year, having moved from 53 in 2022. Direction: worsening (+13.2%).
Oct2022–2024Latest AQI 56+0%
Oct in Ooty averages AQI 56 (Satisfactory) in the most recent year, having moved from 56 in 2022. Direction: stable (+0.0%).
Nov2022–2024Latest AQI 62+2%
Nov in Ooty averages AQI 62 (Satisfactory) in the most recent year, having moved from 61 in 2022. Direction: stable (+1.6%).
Dec2022–2024Latest AQI 88+40%
Dec in Ooty averages AQI 88 (Satisfactory) in the most recent year, having moved from 63 in 2022. Direction: worsening (+39.7%).
Cities with similar (and opposite) seasonal profiles
Ranked by cosine similarity of 12-month AQI signatures across monitored Indian cities.
Similar seasonal profile
Cities whose 12-month AQI signature most closely matches Ooty.
Opposite seasonal profile
Cities whose seasonal signature least resembles Ooty.
What to do with this information
If you are choosing when to visit Ooty or plan outdoor events — marathons, weddings, school sports, outdoor festivals — the CPCB record says July and the two adjacent months are the lowest-risk window. Daily variability still matters; check the live AQI page before committing on any specific date. Sensitive groups should treat May in Ooty as an indoor-air-priority month: close windows on high-AQI evenings, run a purifier with a HEPA filter rated for your room size, and reserve outdoor exercise for clear-weather mornings. On days above AQI 300, even healthy adults benefit from well-fitted N95 or KN95 masks for outdoor commutes.
Frequently asked questions
Which is the most polluted month in Ooty?
May is the most polluted month in Ooty on average, with a long-run AQI of 83 — firmly in the Satisfactory band. This is drawn from 1 CPCB monitoring stations across 3 years of daily readings. Through May, residents should expect elevated PM2.5 and PM10, reduced visibility on cooler mornings, and strong recommendations from doctors to limit outdoor exertion, wear well-fitted N95 masks, and run indoor purifiers through evening and overnight hours when pollutant accumulation typically peaks.
What is the cleanest month to visit Ooty?
July is the cleanest month of the year in Ooty, averaging AQI 47 in the Good band. The months immediately before and after also tend to sit well below the annual mean of 59, so a visit window centred on July is the safest choice for outdoor sightseeing, marathons, school trips and wedding events. Mornings are usually the crispest time to head out; pollution tends to creep up slightly during the evening commute even in the cleanest months. Always cross-check the day-of live AQI before any high-exertion outdoor plan.
Why does Ooty's air spike in May?
Ooty's profile is relatively flat year-round; the small May reflects modest swings in wind, rainfall and local emissions rather than a dramatic seasonal mechanism.
How bad is Diwali air quality in Ooty?
Across the CPCB record, the week around Diwali in Ooty averages AQI 61 — 1.15× the normal October baseline of AQI 53, a spike of 8 AQI points. Firework particulates combine with a cooler, more stagnant late-October atmosphere to produce some of the worst air-quality days of the entire year. Sensitive groups should treat Diwali eve and the two days after as peak-alert days: stay indoors, close windows by evening, run purifiers on high, and reserve any outdoor celebrations for daytime hours when mixing is strongest.
Does the monsoon actually clean Ooty's air?
Yes — meaningfully. Ooty's core monsoon window (Jul 15 – Sep 15) averages AQI 46, a 22% improvement on the annual mean of 59. Rain removes airborne particulates by wet deposition, and the deeper monsoon boundary layer disperses what remains vertically. Across 189 measured monsoon days we see 96.8% in the Good-or-Satisfactory band.
Is Ooty's worst season getting worse or better year-on-year?
Between 2022 and 2024, Ooty's annual average AQI moved from 58 to 58 — a change of +0%. In the most recent year-on-year comparison, the winter season specifically worsened by 12.8%. The long-run direction is roughly stable — underlying growth in emissions is being offset by cleaner technology or weather variability.
Which months are safest to visit Ooty?
July is the single best month at AQI 47. Based on the 12-month averages, the three cleanest months in Ooty are July (AQI 47), September (AQI 47), August (AQI 50). These are the safest choices for outdoor itineraries, long walks, open-air concerts and day-trips. Sensitive groups can treat these months as near-normal activity windows but should still check live AQI for the specific date. Avoid planning outdoor-heavy trips in May, when the baseline jumps into Satisfactory territory.
How does Ooty's seasonal pattern compare to other Indian cities?
Ooty is classified as flat year-round. Based on a 12-month cosine-similarity index computed across all monitored Indian cities, the city whose seasonal signature most closely resembles Ooty's is Salem (Tamil Nadu), with its own worst month in April. Cities with similar signatures often respond to similar policy levers — if a neighbouring peer has demonstrated improvements through specific interventions (construction-dust controls, bus electrification, brick-kiln regulation), they are likely candidates for Ooty too. The peer-city panel on this page lists the closest four additional matches.