01 The rain runs backwards
The figures come from the 1991–2020 normals, with extremes collected since 1867. The annual total is 458 millimetres over 117 days with precipitation, and the annual mean is 15.2 °C. None of that looks extreme until you look at the distribution.
February: 72.1 millimetres. August: 2.1. The same place and the same year, with thirty-four times more water in one month than in another.
The six months from November to April add up to 366.3 millimetres, that is, 80% of the annual total. The three from July to September add up to 10.1. That is the structure of the year, and from it come the only two reasonable windows for visiting.
02 A real winter
January has a mean of 2.3 °C, with highs of 7.2 and lows of −1.3. December is much the same. And there is snow: an average of 27 snow days a year, mostly between December and February, though the maximum recorded depth is a modest three centimetres.
The all-time cold record is −29.5 °C, measured in December, with −28 in January. It is not typical, but it is within what this city can do. And to that you add the lack of light: January and December each have 104.7 hours of sunshine, against July's 386.5.
03 The three dry months
July is the hottest month, with a mean high of 35.9 °C and a daily mean of 28.3, and it holds the all-time record: 44.6 °C. August follows close behind at 34.9. In those two months mean relative humidity falls to 39% and 42%, which makes the heat more bearable than it sounds — but also more deceptive.
What is genuinely hard to take is the light. July has 386.5 hours of sunshine: more than twelve a day. In a city of wide streets, the tree cover stops being decoration and becomes the only way to cross from one pavement to another at two in the afternoon.
04 The two windows
The first is April and May. April has a mean of 15.9 °C and highs of 22.3, and it still rains a fair amount: 63.3 millimetres over thirteen days. May rises to 21.1 and drops to 41.1 millimetres. These are the two months when the tree cover is at its best and the canals carry meltwater.
The second, and for my money the better one, is September and October. September gives a mean of 21 °C, barely 4.6 millimetres of rain and 283.8 hours of sunshine; October drops to 14.4 with 23.7 millimetres. Long days, clean skies, and neither of the year's two discomforts.
If you have to come in summer, use one peculiarity of this city: a good deal of life happens underground or under the trees. The metro is air-conditioned and the central streets have a leaf roof. Organise the day by shade rather than by the clock, and July becomes manageable.
G Da ToledoIt only rains fifty-three days a year here.
Vyacheslav Argenberg HanoiMarch has forty-five hours of sunshine in the whole month.
David Stanley Ashgabat