Viticulture Bulletin: April - July 2024

Synopsis

Whilst world climatic records continued to be broken (hottest ever month of April recorded: 1.58°C above the pre-industrial average - 1850-1900), in the Douro conditions were relatively moderate through most of the spring and the summer (as reported until mid-August). Spring temperatures were either close to or marginally below average, and there was no drought through the season even though rainfall was down by half during April and by twothirds during May. Close to normal levels of rain during June and July helped to mitigate the effects of some heat spikes and a heat wave through July. For this viticultural cycle, accumulated rainfall thus far (November - July) is very close to normal - see figure 1 below.

Fig.1: Quinta do Bomfim – Viticultural Year 2023/24 – Monthly rainfall.

Temperatures in the Douro in April were a fraction above average (deviating by just under +1°C) in the Cima Corgo and marginally below average in the Douro Superior. Much more pronounced deviations from the 30-year average were observed at Fonte Souto (+3.1°C) and at Casa de Rodas (+1.9°C). Rainfall in the Douro was approx. half of what we would expect in most of our quintas; likewise at Fonte Souto and just a 20% drop at Casa de Rodas. Soil water availability came down from 31.4% in March to 29.3% in April (Bomfim).

Rainfall across most of our Douro quintas in May was about a third of what would be considered normal for the month, whilst temperatures – with the exception of Cavadinha – were below average across all properties (deviating by between -0.4°C at Malvedos and -1.6ºC at Vesúvio).

In the Alentejo we had a shortfall in rain to the tune of -85% in tandem with above average temperatures, whilst in Monção-Melgaço we had very generous rain (approx. 50% more than normal) and close to average temperatures.

Flowering (Bomfim & Ataíde): both Touriga Franca and Touriga Nacional began flowering close to the average dates at both Quinta do Bomfim (May 6) and Quinta do Ataíde (between
May 7 and 12).

The Portuguese Met office (IPMA) reported, for the country as a whole, the 5th wettest June since 2000. This was reflected in the three regions where we are present with most of our Douro weather stations recording close to average rain (but noticeably above average in the Douro Superior, especially Canais and Vale Coelho). Temperatures were close to average across our Douro properties.

At Fonte Souto and Casa de Rodas, we recorded approximately 25% more rain in both properties (compared to the monthly averages) and in both cases temperatures were in line with the average for the month.

By the close of June, soil water content as measured by our probes at Bomfim showed good
indices of readily available water (easily available to the vines).

Although the average temperature recorded for July across most of our Douro quintas showed only a moderate increase on the 30-year average (+1°C, approximately), these figures disguise the heat spikes recorded during the first and third weeks, and the heat wave during the last week of the month (with three days above 40°C). This can be explained by the unusually low minimum temperatures registered during a few days in the first half of the month (between 13.7°C and 14.6°C) which levelled out the month’s recorded average temperature. Rainfall was, as a rule, close to average in the Cima Corgo quintas and below average in the Douro Superior properties.

Similarly, Quinta da Fonte Souto and Casa de Rodas recorded monthly temperatures at or close to the average, whilst the former had virtually no rain (1.8mm) and the latter showed close to average precipitation.

Unsurprisingly, soil water content (Bomfim probes) diminished noticeably between the end
of June and the end of July: from 16.9% to 13.4%, which is a fraction below last year’s reading at this time.

Pintor (Bomfim & Ataíde): the pintor (veraison) began from July 8 (Touriga Franca) and July 15 (Touriga Nacional) at Quinta do Bomfim, which is very close to average dates. At Ataíde there was a marginal delay when compared to average dates, although it was a seven to ten day lag comparative to 2023.

Fig.2: Quinta do Bomfim – Viticultural Year 2023/24 – Soil Water Content.

Fernando Alves, Miguel Potes and Joana Valente · August 20, 2024

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Stop press (August 19):
Climate data (Quinta do Bomfim) for the first half of August shows a heat wave during the second week of the month, with five consecutive days above 35°C and zero rainfall. However, the vines are looking in fine condition in the lead up to this year’s vintage in the Douro. The vintage has begun at Quinta da Fonte Souto where we started picking Verdelho on Friday, August 16 (ten days later than last year).