·The Hindu

Is India getting hotter?

In this note
  1. Why in the News
  2. Background & Evolution
  3. Core Static Facts
  4. Multi-Dimensional Analysis
  5. Recent Developments (last 12–18 months)
  6. Prelims Hooks
  7. Mains Relevance
  8. Related Topics to Study Next
  9. Common Errors / Trap Areas
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  • India shows a long-term warming trend in heatwave frequency and duration, even though any single month (e.g., May 2026) may not be extreme by daytime temperature alone [4].
  • Nights are warming faster than days — a critical, under-tracked dimension of India's heat crisis, since heatwave protocols focus on daytime maxima [3][5].
  • Distinguishes short-term weather variability (monsoon onset, El Niño) from long-term climate trend (decadal warming) — a classic UPSC "trend vs. event" analytical frame.
  • Relevant to GS-I (geography/climatology) and GS-III (environment/disaster management).

2. Why in the News

  • Several Indian cities faced heatwave/quasi-heatwave conditions around May 2026; monsoon onset was delayed and an El Niño was expected during June–September 2026 [4].
  • IMD's May 2026 outlook, however, projected 'normal' to 'below normal' daytime maximum temperatures for most of the country, with above-normal readings confined to the southern peninsula, north-east, and north-west [4].
  • All-India May 2026 rainfall was projected at >110% of the long-period average (LPA) [4].

3. Background & Evolution

  • IMD periodically studies heatwave climatology; a key analysis covers the Core Heatwave Zone (CHZ), 1961–2020 [4][2].
  • CHZ comprises: Punjab, Himachal Pradesh, Uttarakhand, Delhi, Haryana, Rajasthan, Uttar Pradesh, Gujarat, Madhya Pradesh, Chhattisgarh, Bihar, Jharkhand, West Bengal, Odisha, Telangana, plus met subdivisions of Marathwada, Vidarbha, and coastal Andhra Pradesh [4][1].
  • IMD/PIB parliamentary replies confirm rising frequency/duration of heatwaves attributed to global warming, based on the 1961–2020 dataset [1].
  • Cities are projected to face a two-fold rise in heatwave days by 2030 per IMD-linked assessments [1].

4. Core Static Facts

Parameter Detail
Nodal agency India Meteorological Department (IMD), under Ministry of Earth Sciences [4][1]
Study period 1961–2020 (60 years) [4]
Heatwave frequency trend (CHZ) +0.1 days/decade (statistically significant) [4]
Heatwave duration trend (CHZ) +0.44 days/decade (statistically significant) [4]
Night-time warming rate ~0.21°C/decade, faster than daytime warming [4][3]
States/UTs with rising night temps 35 of 36 [3]
"Normal" temperature baseline 30-year average at a given station [4]
May 2026 all-India rainfall forecast >110% of LPA [4]
Regions with above-normal heatwave days forecast (May 2026) Himalayan foothills, east-coast states, Gujarat, Maharashtra [4]
Areas with duration trend >1 day/decade Central & north-west India, coastal Andhra Pradesh [1]

5. Multi-Dimensional Analysis

Environmental

  • Long-term warming trend in heatwave frequency/duration is consistent with anthropogenic climate change signals over India [1][4].
  • El Niño (2026) compounds short-term heat/monsoon-delay risk atop the underlying climate trend [4].

Social

  • Night-time heat impairs the body's recovery cycle, elevating heat-stress and mortality risk, especially for outdoor/informal workers and the urban poor without cooling access.
  • Urban heat islands amplify night warming disproportionately in cities.

Administrative/Governance

  • India's official heatwave declaration criteria are daytime-maxima-based; night-time warming is not a primary trigger, creating a policy blind spot [3].
  • Most State Heat Action Plans (HAPs) remain daytime-focused, limiting their effectiveness against the faster-rising night-time heat [3].

Scientific/Technological

  • Distinction between weather forecast (monthly outlook) and climatology (60-year trend) is central to correctly interpreting "Is India getting hotter?" — a single normal/below-normal month does not negate the long-term trend [4].

6. Recent Developments (last 12–18 months)

  • May 2026: Heatwave/quasi-heatwave conditions reported in several cities despite IMD's near/below-normal daytime temperature outlook for most of India [4].
  • 2026: Delayed monsoon onset and forecast El Niño during June–September 2026 raised concerns of compounded heat-monsoon stress [4].
  • 2026: PIB parliamentary replies reaffirmed rising heatwave frequency/duration trends and projected a two-fold rise in city heatwave days by 2030 [1].
  • June 2026: Scientific commentary (Mongabay) highlighted IMD data showing 35/36 states/UTs recording faster night-time warming [3].

7. Prelims Hooks

  • IMD's Core Heatwave Zone (CHZ) study covers 1961–2020.
  • CHZ heatwave frequency trend: 0.1 days/decade increase.
  • CHZ heatwave duration trend: 0.44 days/decade increase.
  • Night-time temperatures in CHZ rising faster than day, at ~0.21°C/decade.
  • 35 of 36 Indian states/UTs show rising night-time temperature trend.
  • CHZ states include Punjab, HP, Uttarakhand, Delhi, Haryana, Rajasthan, UP, Gujarat, MP, Chhattisgarh, Bihar, Jharkhand, WB, Odisha, Telangana + Marathwada, Vidarbha, coastal AP subdivisions.
  • India's heatwave declaration criteria are based on daytime maximum temperature, not night-time minimum.
  • "Normal" temperature = 30-year average for a specific meteorological station.
  • IMD is under the Ministry of Earth Sciences (not MoEFCC).
  • May 2026 all-India rainfall outlook: >110% of Long Period Average (LPA).
  • Cities projected to see a two-fold rise in heatwave days by 2030.
  • El Niño was expected during monsoon months June–September 2026, associated with delayed monsoon onset.

8. Mains Relevance

9. Related Topics to Study Next

  • El Niño–Southern Oscillation (ENSO) — directly linked to India's monsoon and heat variability this cycle.
  • Heat Action Plans (HAPs) — state-level administrative response mechanism to heatwaves.
  • Urban Heat Island effect — explains why cities see amplified night-time warming.
  • National Disaster Management Authority (NDMA) heatwave guidelines — institutional framework for heat as a disaster.
  • India Meteorological Department (IMD) & Ministry of Earth Sciences — nodal scientific/administrative structure.
  • Long Period Average (LPA) rainfall / monsoon forecasting methodology — statistical baseline concepts.
  • IPCC AR6 findings on South Asia — global climate science context for regional trends.

10. Common Errors / Trap Areas

  • Confusing IMD (Ministry of Earth Sciences) with MoEFCC as the nodal heatwave/climate body.
  • Assuming a single "normal/below-normal" month contradicts the long-term warming trend — the two operate on different timescales.
  • Treating heatwave frequency and duration trends as identical figures (they are distinct: 0.1 vs. 0.44 days/decade).
  • Overlooking that India's official heatwave criteria are daytime-based, missing the night-time warming trend as a policy gap.
  • Conflating El Niño (interannual, ocean-atmosphere phenomenon) with the CHZ's decadal climatological heatwave trend.

Sources

  1. 1PARLIAMENT QUESTION: RISING INCIDENTS OF EXTREME HEATpib.gov.in · tier 1
  2. 2Chapter 4: Climatology and long-term trends of Heat Waves, IMDmausam.imd.gov.in · tier 1
  3. 3Science confirms what Indians experience: nights are now warmerindia.mongabay.com · tier 4
  4. 4"Is India getting hotter?", The Hindu, 31 May 2026 (article excerpt)thehindu.com · tier 4
  5. 5IMD Issues Comprehensive Heatwave Guidance as Temperatures Rise Across Regionspib.gov.in · tier 1
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