December 2011 Douro Insider

The first two or three days of the month suggested that it was going to be basically cold, grey and wet, rather predictably.  But the rain immediately dried up and on balance December turned out just to be cold and grey.  The amount of greyness experienced depended entirely on one’s location, however, as the truth of the matter is that there were precious few clouds around in the Douro in December, but plenty of fog.  Low-lying towns and villages, especially those close to the river, spent much of the month barely seeing the sun, nestled as they were below a thick layer of fog.  Those living on the tops of the hills had beautiful blue skies every day, almost without exception, whilst those somewhere in between generally woke up in the middle of the fog but then saw it clear by mid-morning. 

This situation had an interesting effect on the temperatures too.  In Pinhão there was very little difference between day and night time temperatures as the sun never really got through the fog for long enough to make any difference.  It was basically cold all the time.  A little higher up in the hills the clear daytime skies meant that any warmth that had been able to accumulate was swiftly lost at the start of the night, with the resulting condensation bringing down the fog again which then kept in the bitter overnight cold until it eventually cleared once more the next morning.  The cold was not bad from a viticultural perspective; indeed we had started the month with a remarkable number of leaves still on the vines as a hang-over from the very warm autumn.  Dormancy is good for pruning.

The long-awaited and much-needed rainy weather seemed to be arriving towards the middle of the month, but it was not to be.  It dropped only about 30 mm over the course of the week and then normal cold, dry, foggy service was resumed.  With this brief damp spell being the only real exception hitherto, the very stable weather patterns only actually altered again just a couple of days before Christmas.  An anticyclone turned up off the west of continental Portugal, stretching up to the Bay of Biscay, bringing with it still, bright weather but even colder temperatures.  It was around this time that the first frosts were felt in the lower-lying parts of the Douro.  On the high ground they had come about a week before.

Much as the previous paragraphs will have led us to expect, the month of December was below average both in terms of temperature and precipitation.  Pinhão was actually one of the least cold parts of the Douro; its mean temperature of 8.1º C was half a degree below average, yet it was still nearly two degrees warmer than Vilariça, for instance.  Nowhere even reached official ‘room temperature’ and there were two very light frosts in Pinhão.  Other parts of the Douro, by contrast, endured 11 freezing nights, including the entire last week of the month.  There was perhaps a greater spatial variation in temperature than there was in precipitation (which was just very low everywhere).

Pinhão’s 38 mm of rain was not only less than half of the mean, but four and a half times less than fell over the same period last year.  It is not particularly unusual to have such a dry December, however.  2007 was far drier, with just 18 mm, and in 2004 the same month brought an insignificant 6 mm.  The figure above therefore shows that we end the year with an even greater gap between the two lines (actual cumulative total precipitation versus mean cumulative total precipitation) than at any point hitherto.  Monthly rainfall values are remarkable only in that they were consistently below average (10 out of 12 months).  The total rainfall in Pinhão for 2011 was just 447 mm, which translates as a massive 34 % below the long term mean (675 mm).

The second graph (below) compares this year’s temperatures with the mean.  Noteworthy features of the year clearly include the dramatic transition from winter to summer in April.  Then, very unusually, May turned out to be just as hot as June.  This was followed by a relatively cool summer (fortunately, given the poor water status of the Douro soils by this stage) and again a warmer than average autumn.  This meant that by the end of the year the average annual temperature for 2011 came in at 16.3º, a little ahead of the mean (15.9º).

December is perhaps one of the least pleasant months to be working in the vineyards.  Usually very cold, with at least half the morning spent toiling under a heavy blanket of damp fog, and often (though not this year) pouring with rain, it is not a nice time of year to be outdoors.  Added to that is the fact that endless wrist-aching days of tedious pruning is normally all there is to look forward to.  On the plus side, there are of course the end of the month festivities to think about.  Although there were not actually any official holidays this Christmas, what with both Christmas day and New Year’s day falling on a Sunday, it is customary to give the vineyard workers a week off (or even two).  It was, therefore, a rather short month in terms of working days – especially with yet more time lost to public holidays on the 1st and the 8th.

Specifically what we got up to in the vineyards and olive groves of the Douro this month can be easily summed up in two words: see November.  Olive picking, where applicable, was wrapped up over the first few days, before the cold weather brought down the last of the fruit.  It has been less windy than normal so far which is obviously an advantage in this respect but the longer olive picking continues, the more olives have already dropped naturally.  Thus as the winter goes on picking returns become increasingly less which, given the already dubious economics of oliviculture in the Douro, send a clear message that it’s time to stop.

Pre-pruning, pruning and cane shredding also continued exactly as in the previous month.  By the end of the year we would hope to be more than half-way through the pruning (preferably closer to two-thirds) so this was virtually all that went on during December at the vast majority of quintas.  To give an idea of the size of this undertaking, it is worth considering that pruning the vines accounts for approximately one-third of the total annual labour costs in a Douro quinta.  Harvesting the grapes makes up another third, and everything else that goes on over the course of the viticultural year is paid for out of the last third.

There were still one or two properties finishing off fertilisations in selected blocks this month.  After the minerals have been ploughed into the soil they only become available to the vines by dissolving gradually into the soil solution.  Since at the moment the soils are bone dry we really need considerable rain before budburst – or there will be no soil solution.  All the cover crops should have been sown by now, but the same applies: without rain there is no hope of them germinating in the early spring and the money spent on seed will have been wasted.  Elsewhere the only other activities of interest were the surribas: without any rain to bog down the machinery the bulldozers and diggers kept working relentlessly.  At least there will be no delays in this season’s new plantings.  Truly a meagre silver lining in a cloudless sky…