Record month for hospital emergency units
The number of patients going to A&E units in Wales last month was the highest on record.
July is often the busiest month, while winter tends to bring more elderly patients with complex conditions.
Latest figures show 99,552 patients went to emergency units in July, of these, 77.4% were seen within the four-hour target.
The Welsh Government said it had been an "extremely challenging" month for frontline emergency services.
Wrexham Maelor Hospital, which has been the worst performing A&E, showed improvement with 56.3% treated, discharged or transferred within four hours.
More than a million patients have attended A&E in Wales over the last year.
However, 4,922 patients waited more than 12 hours during July - a rise on the previous month - which the Welsh Government called "disappointing".
A Welsh Government spokesperson said: "Last month proved extremely challenging for front line emergency health services."
July also saw the second highest daily average volume of red calls (the most critical) for the Welsh Ambulance Service, since its new response model was introduced nearly four years ago.
"Despite these pressures the vast majority of people have received timely advice, care and treatment," said the spokesperson.
"We recently announced an extra £50m to tackle the longest waiting times and expect to see improvements made this year.
"We are also working with the NHS to reduce the pressure on emergency departments. This includes helping more people to remain independent at home, focusing on vulnerable groups who need care the most and increasing capacity."
Jo Mower, vice president of the Royal College of Emergency Medicine in Wales said: "It is essential to maximise the potential of same day emergency care across Wales by offering our patients real alternatives to attending their local emergency departments.
"At the same time, we need to improve timely discharge of those patients who are medically fit and are ready to go home safely."
The body representing health boards said demand on emergency units was now all year round and there would be similar headlines unless "we capitalise on the momentum" from the Welsh Government's long-term plan to revolutionise health and social care, which aims to see fewer patients treated in hospital.
"We now need to see transformation delivered at pace and scale so we can continue to deliver high quality services which people rightly expect in Wales," said Nesta Lloyd-Jones, interim director of the Welsh NHS Confederation.
Conservative health spokeswoman Angela Burns said: "It is obvious to anyone who looks that winter pressures is no longer a phrase that does justice as thousands are made to wait hours longer than they should at all times of the year.
"The record number of A&E patients shows the Welsh Government need improved preventative measures and expanded awareness of other ways to seek treatment without adding pressure to besieged emergency departments."