Slithering out of concealment into the Mediterranean temperatures, the UK's reptiles are delighting in the British heatwave.
By Alex Kirby
BBC News Online environment correspondent
That means more encounters with people, and more people upset and frightened by what they see.
English Nature, the government's wildlife advisers, have published a guide to identify reptiles and reassure the anxious.
They expect even more snakes to be out and about once the weather breaks and rain returns.
English Nature's enquiry service has been busier than usual with reported reptile sightings since the hot weather began, but says about 95% of calls are a case of mistaken identity.
The organisation's reptile specialist, Jim Foster, said: "We appreciate that some people are terrified when they first see a snake in the garden, but there is rarely anything to be truly worried about.
"Snakes and lizards get a bad press, but the message this summer is - stay calm if you spot a snake!
Adder: Venomous, shy and rarely fatal
"The hot weather doesn't mean there will be more snakes, but sightings are more common because people are outdoors while snakes are moving around.
"Even if you are lucky enough to spot an adder, there's absolutely no need to harm it as helpful advice is only a phone call away."
Mr Foster says grass snakes and slow-worms, which are harmless, often visit gardens, while adders, which are venomous, rarely do so.
England is home to grass snakes, adders and smooth snakes, and to common lizards, sand lizards and slow-worms, slug-eating legless lizards.
It is illegal to kill or injure any of them, with fines of up to £5,000 and six months' imprisonment for offenders.
Grass snake eggs
Jim Foster told BBC News Online: "Sadly, the evidence is that reptile numbers are dropping across much of the countryside.
"Adders are declining at about a third of the sites they frequent, and where they're monitored there's evidence that grass snakes are vanishing too.
"They like places like muck heaps on farms, and as those go there are fewer places for the snakes to live. The loss and deterioration of their habitat is their main problem.
"The good news is that you can help grass snakes, for instance by putting a compost heap or a log pile in your garden.
"The people who ring us up are often quite distressed - it's the first time they've ever seen a snake when they find one on their doorstep, or the cat brings one inside.
Not a snake, but a lizard: Slow-worm
"We try to be sympathetic, and often spending a few minutes talking to them or sending a volunteer round to see them will clear up the problem.
"But a small minority of people do suffer from genuine ophidiaphobia, and whatever we do they'll be afraid of snakes."
English Nature's guide, Reptiles In Your Garden, is downloadable from the organisation's website.
Snakes in the UK can become quite lethargic if the heat is persistent, but the current heatwave seems to have proved almost ideal for them.
English Nature says the chance of seeing a snake when heavy rainfall follows a prolonged dry spell "dramatically increases". Rain is forecast for much of the UK in the next few days.
Coiled adder image courtesy of Graeme Skinner/Naturally Wild, others by Jim Foster/English Nature.