Vejret i Alleppey (Alappuzha) i december

November to February is the Kerala season and December its peak, which regulars translate into one instruction: book the houseboat months ahead, because the good ones are gone and last-minute is luck rather than choice. Crowds are the corresponding cost. On weather they describe the dry season beginning, and our row suggests beginning rather than begun - 74.6mm across 10.1 precipitation days is about seven millimetres a wet day, the tail of the northeast monsoon still working through the first half of the month. The other thing the row shows is stillness: 29.5C at 82 percent humidity with an 8.2 kph wind reads as 35C, and the nights at 23.9C feel like 29C. The backwaters are sultry, not breezy. The record: 9.7 hours of sun, a 29.6C sea and AQI 92.

Regulars are specific this counts as the tail end of the monsoon here, the later in the month a trip lands the drier conditions tend to be, mornings and nights staying cool while daytime turns properly sunny and hot along the backwaters. Our row backs that hot, genuinely wet read, 28.9C reading as a scorching 35C, over 24.2C nights feeling 29C, with a substantial 199.8mm of rain across 19.9 days and humidity at 87 percent. Regulars are consistent coastal daytime temperatures commonly cited in the 30 to 36C range, the backwaters themselves warm and humid but described as genuinely relaxing despite that. Real air quality is also worth factoring in this time of year given regional conditions. The sea sits at a warm, swimmable 30C. The record: 8.5 hours of sun, a 7.8 kph wind and AQI 88.

Regulars are blunt about this month: hot and humid, especially by mid-April, with the backwaters offering little natural shade of their own. Our row backs the intensity, 32.3C reading as a real 39C at 79.7 percent humidity, over 26.1C nights, with 160.9mm of rain across 25.3 days already signalling the approach of the monsoon. On the water itself, though, more than one houseboat traveller describes a steady breeze that keeps a covered deck comfortable through the day despite the heat on land. The practical advice for a houseboat booking is to check the air-conditioning tier carefully: premium boats typically cool the bedroom only overnight, while luxury boats run it around the clock. The sea off this coast holds a very warm 30.7C. The record: 10.7 hours of sun, an 11.5 kph wind and AQI 94.

March starts the Kerala hot season and regulars do not soften it: 24 to 35C with humidity around 80 percent, and walking a town in it means moving shade to shade. Our row reads 32.8C over 25.7C nights, which the humidity turns into 39C and 31C. What makes the month work here is the thing people come for anyway - on a houseboat under way you do not feel it, because the movement and the water do what no amount of shade ashore can. Rain is not yet a factor: 63mm across 13.6 days. The figure worth checking before a long stay is the air: AQI 105, the highest in this batch by a wide margin. The record: 10.9 hours of sun, a 12.6 kph wind and a 30.1C sea.

January is the pick of Kerala's backwater season - roughly November to February, outside the monsoon, which is what the houseboats are for - and the forum's advice about Alleppey is almost entirely about booking. The stretch from about 20 December to 10 January is the peak: rates rise, the water gets busy, and the good boats are taken months ahead, so a last-minute one is a matter of luck rather than planning. Two things shape the evening before you plan one. Houseboats do not cruise after six as a rule, and the day is short here, so the light you actually get on the water is the afternoon. The record: 30.6C days that feel like 36C, 23.6C nights, 4.7 precipitation days carrying 38.4mm, humidity 76 percent, 10.3 hours of sun, a 28.6C sea and AQI 124.