The year in Kunming, at 1,888 metres
The figures are the provincial capital's, in the middle of the plateau. The annual total is 991 millimetres of rain over 121 days and 2,240.9 hours of sunshine. The scoring does not measure heat — which barely moves — but how much it rains and how much light is left.
There are cities whose climatic nickname is advertising and cities where it is a description. Kunming belongs to the second group: they call it the city of eternal spring and, looking at the table, it is hard to find an objection.
And that has an awkward consequence for anyone planning: the variable almost everyone uses to pick a month — temperature — is useless here, because it barely moves. Something else decides.
01 Nine degrees in twelve months
These are the average highs month by month: 16.3 in January, 18.5, 21.8, 24.3, 25.2, 25.4, 24.8, 25, 23.5, 21.1, 18.7 and 16 in December. From the coldest month to the warmest there are 9.4 degrees of difference.
The lows cover a slightly wider range, from 4 degrees in January to 17.6 in July, and that is winter's only real discomfort: the mornings are cold. But no month of the year reaches 26 degrees of average high or drops below 16.
The explanation is altitude. Kunming sits at 1,888 metres at a subtropical latitude, and that combination produces a mild, stable highland climate. It is the same mechanism that makes the whole province cooler than its position on the map suggests.
02 What does move
Swap the temperature column for the rainfall one and a completely different year appears: 23.8 millimetres in January, 11.9, 19.6, 25.4, 80.1, 173.1, 215.7, 195.9, 119.3, 82.4, 30.1 and 13.7 in December.
From February to July the figure multiplies by eighteen. And wet days tell the same story more clearly: 3.7 in February against 19.7 in July. In February it rains less than one day a week; in July, almost five.
And the third column, sunshine, is the one that most directly affects the trip: 223.6 hours in January, 253.3 in March, 122.6 in July, 127.1 in September, 195.4 in December. Between March and July, 130 hours of light a month are lost, more than four a day.
03 The May switch
The change is not gradual: it has a specific month. April leaves 25.4 millimetres over 6.5 days; May, 80.1 over 11.1; June, 173.1 over 16.5. In sixty days rainfall multiplies by seven.
That jump is the monsoon arriving, and it marks the real boundary of the Yunnan calendar. More than half the year's rain falls between June and August, in a province that totals 991 millimetres a year over 121 days.
May is therefore the last usable month of the dry block, and it should be treated as what it is: a transitional month with 217.2 hours of sunshine and eleven wet days. It works, but it is no longer March's sky.
04 Summer's coolest month is in summer
Here a detail turns up that throws people. The warmest month of the year is neither July nor August: it is June, with average highs of 25.4 degrees. July stops at 24.8 and August at 25.
The reason is cloud. When the monsoon settles in, the sky covers over and the radiation reaching the ground drops, so the thermometer stops rising even though the calendar says high summer. July has 122.6 hours of sunshine against June's 148.
So the wet season is not suffered for heat: it is suffered for lack of light. It is mild rain, in a mild city, under a covered sky. For photographing mountains or terraces, it is the worst possible scenario.
The year's four stretches
Between 11.9 and 30.1 millimetres of rain a month, with 3.7 to 6.5 wet days and between 191.5 and 253.3 hours of sunshine. Highs climb from 16 to 24.3 degrees. Six consecutive months of clear sky: this province's real season.
Rain jumps from 25.4 to 80.1 millimetres and wet days from 6.5 to 11.1, but sunshine holds at 217.2 hours and highs sit at 25.2 degrees. It is the last usable month before the monsoon, at half the risk.
173.1, 215.7 and 195.9 millimetres, with up to 19.7 wet days in July and the year's sunshine minimum, 122.6 hours. More than half the annual water falls in these three months. In exchange, it is wild mushroom season.
Rain drops from 119.3 to 82.4 millimetres, but sunshine stays at 127.1 and 143.2 hours, below even August. It rains less and stays cloudy: the stretch with the worst water-to-light ratio in the whole year.
05 What the wet season gives you
It would be unfair to dismiss the monsoon without saying what it brings. The first answer is agricultural: the southern terraces are worked with the year's water, and the green landscape in summer photographs is a direct consequence of those 215 July millimetres.
The second is gastronomic and very specific. Yunnan's wild mushroom season runs from June to August and depends entirely on the rain. It is the only moment of the year when you can eat what makes this province famous among people interested in fungi.
What you lose, though, is the mountain. With 122.6 hours of sunshine in July, the north-western peaks are covered most of the time, and the high-mountain trip — the reason many people come — stops making sense.
06 How to choose the month
If the trip is about mountains and landscape, the block is November to April and the month is March: 253.3 hours of sunshine, the year's maximum, with only 19.6 millimetres of rain and average highs of 21.8 degrees.
If dryness matters above all, February wins with 11.9 millimetres over 3.7 days. And if you want temperature without giving up the sky, April combines 252.2 hours of sunshine with highs of 24.3 degrees.
And if the trip falls in the wet season anyway, choose June over July or September: 173.1 millimetres against 215.7, and 148 hours of sunshine against 122.6 and 127.1. It is the least bad month of the block, and it opens the mushroom season too.
