Delhi (New Delhi) — sää kuukausittain

The climate in Delhi goes through five distinct seasons. Winter, from December to January, is cold (the temperature drops to near freezing at night though the days are warm) and is notorious for the thick layer of smog that hangs over the city, resulting not only in cancelled flights and delayed trains, but also warnings to stay indoors and wear high-quality masks if you need to venture out. Spring, in the months of February and March, is pleasant with warm days and cool evenings. Summer, in April and May, is uncomfortably hot with temperatures soaring as high as 45 °C. Temperatures moderate during the monsoon season (June to September), but it is humid. Autumn, from October to November, brings warm days with relatively cool nights.

Regulars separate two things travellers usually confuse. The winter fog, which disrupts flights and road trips, normally clears by the start or middle of February. The air pollution does not: it is there all year, worst in December and January, easing as the month warms, and visible or not depending on the day. Our AQI of 150 is what the easing looks like: an improvement rather than clean air. The weather itself is the easy part - 25.7C by day over 10.4C nights, 28.5mm of rain across 2.4 days, and mornings cold enough for a jacket. Several regulars travel with a mask and say they are easy to buy on arrival. The record: humidity 67 percent and 9.8 hours of sun.

Delhi's forum calls March the tail end of the pleasant winter season, sunny and warm around 30°C by mid-month, with light cotton clothing and sun protection the standard advice. Regulars are consistent that the city starts genuinely heating up after the first couple of weeks, so March is a better bet earlier in the month than later.

Delhi forum regulars answer “is April unbearably hot” mostly with yes, but a manageable one: “expect 35-40°C,” some posters reporting “38 to 42 degrees,” though the heat is “hot but less humid compared to May and June.” The standard survival plan is specific — avoid sightseeing 12-4pm entirely, front-load activities into early morning and evening, hire an AC car, keep a hotel with reliable AC, and cover skin with loose clothing and a wide-brimmed hat rather than fight the sun directly. The consolation regulars offer: April is genuinely low season, so hotel rates drop and crowds thin at the sites that stay busy October through February. Our record: 35.7°C days, 19.8°C nights, 3.4 rain days and an AQI of 118 — properly hot and dry, matching the “unbearably hot but doable with a plan” read.

Delhi forum regulars call May the peak of the heat, harder than April: “temperatures can touch up to 48 degrees Celsius,” typical daytime readings “45-47 degrees,” and very hot and dry (not humid) — the dry heat wave locally called “Loo” intensifying through May and June. The survival plan is the same one regulars repeat every summer month: sightsee early morning, retreat to an air-conditioned hotel or taxi through the afternoon, and only venture out again after 5pm when the heat starts easing. The consolation prize: genuine off-season hotel deals and thin crowds at sites that are packed October through February. For anyone with flexibility, regulars point toward Kashmir, Leh, Ladakh, Shimla or Manali instead — cooler mountain alternatives for the same dates. Our record: 37.3°C days, 23.6°C nights, 47.7% humidity and an AQI of 146 — properly extreme dry heat, matching the “worse than April, dry not humid” read.

Delhi-forum threads on June weather confirm this is genuinely the hardest stretch of the year to be outdoors, temperatures regularly pushing past 40C in the pre-monsoon build-up, the proper monsoon itself not arriving until well into July. Posters describe the heat as furnace-like by early afternoon, and the standing advice is to lock sightseeing into the very early morning or after sunset, avoiding the roughly noon-to-4pm window entirely. Loose cotton clothing, a hat, sunglasses and constant water are called essential. A handful of scattered afternoon storms do roll through as the month progresses, offering brief relief before the heat rebuilds within a day. Regulars are blunt that June rewards flexible, air-conditioned plans far more than ambitious walking itineraries. The record: a scorching 39.3C by day feeling like a punishing 44C, 27.1C nights, 54 percent humidity, 11.6 hours of sun and an unhealthy 139 AQI.

Delhi forum regulars describe September as monsoon's fade-out, not its end: early September “can still be rainy...just rain once every few days,” while by late September “the monsoons are over with a lot less chance of rain” and evenings turn more pleasant. Temperatures run “22-33°C” through the month, with the humidity from the retreating monsoon doing as much to the comfort level as the number itself. Forum consensus leans toward October being the better bet if dates are flexible, but several posters note September already works for Delhi/Agra/Jaipur/Varanasi with discounted hotel rates as a side benefit. Our record: 32.3°C days, 24.7°C nights, 13 rain days and 75% humidity — hot and still properly humid, the fade-out the forum describes rather than a clean break from monsoon.

Delhi's forum rates October among the best months to visit, moderate temperatures around 25°C by day and 10°C at night, past the monsoon and before winter's smog really sets in. Regulars flag air quality as the real wildcard this time of year — stubble burning ahead of Diwali can degrade it — so October is good weather-wise but worth checking pollution forecasts closer to the date.

I’ve been in Delhi in November and it is horrific. The role of stubble burning is massive.