Air cooler or AC in Kolkata? Climate verdict, tonnage, season
Bay of Bengal moisture makes April’s 36 °C feel like 45: Kolkata is a city of window ACs humming from heritage buildings, where an air cooler only ever moves damp air around — that is summer in Kolkata, and it decides the right machine.
| State | West Bengal |
|---|---|
| Peak temperature | ≈ 36 °C (hottest month, typical) |
| Humidity at peak | ≈ 70% RH (afternoon) |
| Hot season | April to June, humid all summer |
| Air cooler verdict | humid: AC only |
What Kolkata’s climate decides
In Kolkata, skip the air cooler — 70% humidity at 36 °C defeats evaporation before it starts. The season (April to June, humid all summer) calls for a split AC with dehumidification priority, anti-corrosion coils if you are near the sea, and filters cleaned monthly against the damp-season biofilm.
Sizing an AC here
For Kolkata, the working rule is 1 ton for a bedroom, 1.5 tons for a large room — with dry mode prioritised. Read the BEE label’s ISEER and annual kWh rather than star count alone, and in this humid regime, prioritise a genuine dry mode and long gentle cycles. Guides: split ACs, BEE stars, inverter tech.
Brands compared for India — Voltas, Blue Star, Lloyd, LG for ACs; Symphony, Bajaj, Crompton, Havells for coolers — on our brand pages; the air cooler guide covers desert vs tower vs personal sizing.
Frequently asked questions
Does an air cooler work in Kolkata?
No — this is AC territory — Kolkata’s coastal or basin humidity (36 °C, ~70% RH at peak) is the reason. Our evaporative cooling guide explains the wet-bulb physics behind the verdict.
What AC tonnage do I need in Kolkata?
Rule of thumb for Kolkata’s 36 °C peaks: 1 ton for a bedroom, 1.5 tons for a large room — with dry mode prioritised. Oversizing is the classic mistake — a too-big unit short-cycles and leaves rooms clammy in the humid weeks; see the sizing guide.
Same verdict elsewhere in India: Bhubaneswar · Chennai · Guwahati · Kochi · Mumbai.