LAST winter was the “single, longest wettest period” Joseph Atkin has known as head gardener at one of Carmarthenshire’s best known attractions.

“We are now on the way to one of the single, longest driest periods,” he said.

The flip in the weather after heavy winter rainfall, which culminated in two destructive storms – Ciara and Dennis – has been eye-opening.

The skies cleared in March and April was the sunniest on record in the UK – although in Wales it was third sunniest. The average temperature in many areas in April was 3C above normal.

The turnaround couldn’t have been better timed as the country faced the psychological dislocation of the coronavirus lockdown.

The largely dry and warm conditions – albeit with some sharp frosts thrown in – have continued during May and there is little indication of change, in west Wales at least, until June at the earliest.

But it is starting to make some people twitchy.

Mr Atkin, of Aberglasney Gardens, Llangathen, in the Towy Valley, said: “We have never done this much watering before June.

“We can cope – we have tactics to make sure we are drought-tolerant.

“We keep on with the mulching process. The established plants should manage okay.

“And we have some natural springs through the site.”

A thunder storm a couple of weeks ago, he said, drenched Gorslas a few miles south but left the gardens bone dry.

“If you look at the weather data, records are being broken,” he said. “I do find the weather more extreme.”

Mr Atkin said trees were more susceptible to sustained dry conditions in spring because their developing foliage lacked the waxy surface on top which helped prevent evaporation.

“It means the leaves will ‘sweat’, and the tree needs to suck up more water,” he said.

“Dry weather in the spring is far more likely to kill a tree than later in the year. The tree has to develop a defence mechanism.”

Mr Atkin said trees’ leaf litter from the previous autumn, like gardeners’ mulch, helped retained moisture in the ground.

And every species of tree, he said, had a complex underground relationship with fungus involving hidden exchanges of nutrients.

Carmarthenshire dairy farmer Dai Gravell and his son Thomas said the weather since last autumn had been challenging.

“The rain started early, and it was the wettest February on record,” said Dai.

“That bring problems because slurry pits fill up a lot quicker.

“To comply with environmental regulations, dirty water that fills the yards has to go into a slurry pit.”

Full slurry pits have to be emptied quicker, he said, and that meant extra costs.

The 57-year-old said farmers have been cutting silage earlier than normal this spring.

“You may have a nice crop of grass now, but you know you have reached a line because you need rain for it to grow back,” he said.

“Grasses should be growing like billy-o, but they’re withering in this heat and dryness.”

Without rain, he said, there was a strong possibility that farmers would have to feed silage to their cattle in the summer, instead of from October onwards.

Dai said milk prices had dropped due to the hospitality industry virtually shutting down since the end of March.

“So that’s a double whammy,” he said. “You need a good season just to compensate.”

Dai, who is chairman of Carmarthenshire NFU Cymru, said farmers had been dealing with weather extremes over the past five or six years.

He said: “We seem to be breaking records in a very short period of time. All we need now is three metres of snow – it wouldn’t surprise me!”

A spokeswoman for NFU Cymru said farmers’ focus remained on keeping the nation fed.

She added: “Growth of spring sown arable crops are also being impacted.

“On many farms some winter crops failed as result of the extended waterlogged conditions, these fields have now been replanted with spring sown crops and these young plants are in now in need of some significant rainfall.”

River levels in west Wales at the end of April were below normal, notably low or exceptionally low compared to the 1981-2010 average, according to data from the UK Centre for Ecology and Hydrology. Most were exceptionally high two months previously.

Seven species of fish migrate from the ocean to rivers such as the Teifi to spawn in Wales, including salmon, sea trout and eels.

Peter Gough, principal fisheries adviser for Natural Resources Wales (NRW), said salmon and sea trout mainly entered rivers between March and October, waiting until November to spawn.

Their offspring make the journey the other way after two years, usually in the spring.

“All of these journeys are affected to some extent by river flow and water temperature conditions,” said Mr Gough.

Flood events “triggered” adult fish to head upriver, he said, where they waited for autumn rainfall to reach the final spawning areas.

Low river flows and warm water delay these migrations.

Mr Gough said: “The general pattern of warming of rivers is a threat to salmon and sea trout, which are basically cold-water species.

“It can lead to disrupted migrations and the risk of mortality.

“In the winter of 2015-16 water temperatures reached their highest levels known, and this seriously damaged the breeding success of salmon and – to a lesser extent – trout.”

He said this would still affect the number of salmon returning to Wales’s rivers in 2020.

NRW monitors river levels in Wales – some every 15 minutes.

An NRW spokeswoman said levels were low for this time of year, although some rivers and tributaries were currently within a “normal banding”.

Utilities like Welsh Water monitor reservoir levels, which provide most water to customers.

It also keeps a close eye on rainfall, river flow, groundwater levels and demand. Welsh Water publishes annual drought plans.

There are five indicators which identify when the water resource situation is moving into a drought – from normal operation all the way to emergency measures.

A spokesman for Welsh Water said: “At this stage, we do not have concerns about our water resource levels – but given the recent dry and hot weather, we are monitoring the situation to ensure that, if this weather persists, we are able to manage our network to maintain water supplies.

“We also – as always – ask customers to use the water they need, particularly to ensure they remain safe and healthy, but not to waste any water.”