The average price tag on a home fell by just over £650 in July – marking the first month-on-month tumble in 2019 amid signs the market is turning more in favour of buyers.
Across Britain, the average asking price is now £308,692 – 0.2% or £656 lower than in June, Rightmove said.
Rightmove said the typical time it takes sellers to secure a buyer is the longest for this time of year in six years.
The average time to sell is 62 days, the longest for the summer since 2013.
The findings suggest sellers risk their properties going “stale” and sitting on the market for long periods if they do not adapt to current market conditions.
Longer selling times and higher numbers of homes on estate agents’ books suggest it will be more of a buyers’ market in the second half of 2019, the report said.
Fewer properties are coming to market, with the numbers down by 7.8% in July compared with the same period a year ago, Rightmove said.
Because properties are sitting on the market for longer, the numbers on estate agents’ books have increased to 53.3 per branch – the highest number since an average of 54 in July 2015.
Rightmove director Miles Shipside said: “The housing market fundamentals remain largely sound in many parts of the country, but the current political climate means that the crucial ingredient of confidence has been impaired, and that is causing some potential buyers and sellers to hesitate.
“Those who have postponed their purchase should note that estate agency branches have more sellers on their books than at any time for the last four years, so there should be more choice of properties to buy.
“It could be a good opportunity to negotiate a relative bargain in the second half of the year, if they can set aside the continuing Brexit distractions.”
Rightmove also quoted the views of estate agents.
Lucian Cook, head of residential research at Savills, said there are early indications that a “ripple of caution” which has been constraining price growth in the South East of England is spreading more widely.
He said: “Protracted political hiatus has added to the sense of caution over the prospects for household finances, even though mortgage debt remains cheap.
“These market conditions have sorted the needs-based movers from the discretionary ones who are often in larger properties.
“They also mean that selling in the current market requires a healthy dose of pragmatism, which is reflected in a decline in asking prices.
“Where that has been taken on board, stock has continued to trade.
“That presents opportunities for those looking to trade up the ladder, though they need to be as realistic about the value of their own property as about the one that they want to purchase.”
Shaun Adams, managing director of Sussex-based Cooper Adams and a Fine and Country branch, said: “For us, the market was quite dire at the start of the year but things have livened up from June onwards.
“Maybe lots of people are sick of waiting for Brexit to happen and are just getting on with things, but we anticipate there might be another lull in the run-up to the October 31 deadline, although thankfully that hasn’t happened yet.
“The market right now is still quite buoyant but it is changing.
“Beforehand if a seller was optimistic, they would most likely still get their valuation, whereas now they could alienate potential buyers and have their property go stale.”