Most advice about when to visit Rajasthan resolves to "not summer", which is correct and unhelpfully vague. The meteorological department publishes the underlying figures, the criteria under which it declares a heat wave, and the warning colours you will see if one is declared while you are there. Those are more useful than a season name.
What Jaipur's heat actually looks like
The department's station chart for Jaipur Sanganer gives the monthly normals.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Mean max °C | 22.6 | 25.7 | 31.6 | 37.4 | 40.7 | 39.6 | 34.6 | 32.7 | 34.2 | 33.8 | 29.3 | 24.5 |
| Mean min °C | 8.6 | 11.4 | 16.8 | 22.2 | 26.5 | 27.7 | 26.1 | 24.8 | 23.6 | 19.6 | 14.0 | 9.5 |
April already averages 37.4 degrees as a maximum. May peaks at 40.7 and June is barely lower at 39.6 with a higher overnight minimum of 27.7 — which is the number that matters for sleeping and for recovery between days out.
The record extremes give the ceiling. IMD's compilation to 2012 records Jaipur Sanganer's highest maximum as 48.5 degrees on 6 May 1980, with 47.2 in June 1897 and 46.7 in July 1901. Across Rajasthan the highest in that compilation is Alwar at 50.6 degrees on 10 May 1956, followed by Dholpur and Sriganganagar at 50.0 and Barmer at 49.9.
The criteria that trigger a warning
The department's 2021 standard operating procedure sets out the thresholds, and knowing them lets you read a forecast rather than a headline.
In the plains, a station must first reach at least 40 degrees Celsius; in hilly regions, 30. Once that qualifying threshold is met, a heat wave is declared on a departure from normal of 4.5 to 6.4 degrees, and a severe heat wave above 6.4. Alternatively, an actual maximum of 45 degrees is a heat wave and 47 a severe heat wave. The criteria must be met at a minimum of two stations in a meteorological sub-division for two consecutive days, and the declaration is made on the second day.
The department also tracks warm nights, considered only when the maximum stays at 40 degrees or above: a warm night is a minimum departure of 4.5 to 6.4 degrees, a very warm night above 6.4. Normals used for these comparisons are for 1981 to 2010.
Its colour system runs across all weather warnings: green is no warning and no action, yellow is watch and be updated, orange is alert and be prepared, red is warning and take action.
For heat, the department publishes what each colour means in practice.
| Colour | Trigger | What it means for you |
|---|---|---|
| Yellow | Heat wave at isolated pockets for 2 days | Tolerable for most; moderate concern for infants, the elderly and those with chronic conditions |
| Orange | Severe heat wave for 2 days, or heat wave for 4 days or more | Increased likelihood of heat illness with prolonged sun exposure or heavy work |
| Red | Severe heat wave for more than 2 days, or over 6 heat wave days in total | Very high likelihood of heat illness and heat stroke in all ages |
The public guidance the department reproduces from the national disaster authority is practical rather than dramatic: carry water while travelling, drink even when not thirsty, wear lightweight light-coloured loose cotton, cover your head, use oral rehydration salts or buttermilk, schedule strenuous activity to cooler hours, and recognise weakness, dizziness, headache, nausea and heavy sweating as warning signs requiring a doctor.
When the rain arrives and where it goes
The department's normal onset over Kerala is 1 June, with the monsoon covering the entire country around 8 July. For Rajasthan specifically, its 2025 monsoon report gives 18 June as the normal date the monsoon reaches the state and 8 July as the normal date the whole state is covered. Withdrawal normally begins from west Rajasthan on 17 September, with the whole of Rajasthan normally clear by 30 September, and withdrawal from the southern peninsula and the entire country around 15 October.
Rainfall normals for 1971 to 2020 give the distribution by district.
| District | Jun | Jul | Aug | Sep | Annual |
|---|---|---|---|---|---|
| Jaipur | 66.8 | 202.3 | 181.0 | 74.2 | 587.9 |
| New Delhi | 74.1 | 209.7 | 233.1 | 123.4 | 774.3 |
| Chennai | 64.6 | 107.3 | 133.6 | 143.0 | 1346.4 |
Jaipur's July and August together come to 383.3 mm, about 65 percent of its annual total. Outside those two months the district is close to dry: October through December totals 19.9 mm.
Chennai is the opposite case and shows why a national monsoon calendar misleads, in the same way that northern and southern indicators diverge. Its October, November and December bring 274.5, 370.6 and 164.6 mm, about 60 percent of its annual rainfall, under the north-east monsoon. The department's 2025 report notes that the south-west monsoon's complete withdrawal on 16 October that year "also marked the commencement of Northeast Monsoon rainfall over the southern peninsular regions".
What the state itself advises
Rajasthan Tourism's own guidance is worth reading because it is franker than most promotional material. It states that summers last from April to June, are "particularly harsh", with "temperatures rising up to 48°C during the day", and that around the Thar Desert conditions are harshest.
Its summer advice, if you travel anyway, is to head for Mount Abu, Kumbhalgarh or Ranakpur, and that in other cities the weather is workable "in the early mornings and late evenings, and it is advisable to stay indoors otherwise". It recommends sunscreen and light, full-sleeved cotton.
On seasons, it names winter as generally the best time, running from around October to January with temperatures between 10 and 30 degrees, and describes July to September as a particularly good time to avoid crowds as temperatures drop across the state.
That last point is the one visitors miss. The monsoon months in Rajasthan are not a washout; they are the quiet season in a state whose peak season is uncomfortably busy.
Practical reading of the calendar
October to March is the comfortable window, though festival weeks crowd its first half, with December and January coldest at a mean minimum of 9.5 and 8.6 degrees in Jaipur — cold enough at night to need a layer, which surprises people who packed only for desert heat.
April to June is avoidable if you have a choice and manageable if you do not, on the department's own terms: plan outdoors for early morning and late evening, watch for the orange and red heat alerts, and treat 45 degrees as a threshold at which the day's plan changes rather than an inconvenience.
July to September trades crowds for rain, which in Jaipur means roughly two wet months rather than a wet quarter.
What this guide does not cover
No monsoon onset date is given for Jaipur city, or for Mumbai, Delhi or Kolkata. The department publishes city-level onset only as map isochrones with no city markers, so only its state-level and national dates appear above.
The averaging period for the Jaipur temperature and station-chart rainfall figures is not stated by the department on the page publishing them. The district rainfall normals are separately labelled 1971 to 2020, which is why the two rainfall series differ slightly — they are point-station and district-areal measures over unstated and stated periods respectively.
No Rajasthan temperature record after 2012 is stated, because none could be verified from a departmental source.
The national disaster authority's own site was unreachable. Its heat guidance above is quoted as the meteorological department reproduces and cites it in its 2021 procedure, not read from the original.
No Rajasthan state disaster authority heat action plan was retrieved; the state government portal was unreachable.
Rajasthan Tourism's own seasonal temperature and rainfall table conflicts substantially with the department's normals and is not reproduced here. Where the two differ, the meteorological figures are used.