The chief executive of NHS Wales Dr Andrew Goodall said there were "encouraging signs" but has warned of a possible second or third peak at a briefing today.
It comes as the latest figures showed 624 people have died in hospitals in Wales - with 15 more deaths reported yesterday.
While 18,100 people have died in the UK from Covid-19.
But England's chief medical officer has said the likelihood of having a coronavirus vaccine in the next calendar year is "incredibly small".
Professor Chris Whitty said people should be realistic about how long it would take for an effective Covid-19 treatment or vaccine to be developed.
However, he added that he was "very hopeful" vaccines which have proof of concept will be available much earlier than a year.
Speaking at the daily Downing Street press conference, Prof Whitty said: "In the long run, the exit from this is going to be one of two things, ideally.
"A vaccine, and there are a variety of ways they can be deployed... or, and or, highly effective drugs so that people stop dying of this disease even if they catch it, or which can prevent this disease in vulnerable people.
"Until we have those, and the probability of having those any time in the next calendar year are incredibly small and I think we should be realistic about that."
Send a heart to our #NHSheroes
It is something that has, at some point, touched all our lives.
From cradle to grave, the National Health Service, and the incredible professionals within it who care for us, is a part of British life.
Today, more than ever, we should cherish those who dedicate themselves to our care, heedless of their own health as they work tirelessly to care for people in the face of the coronavirus pandemic.
Nurses and others - employed by the NHS and any other part of health and care - we have never needed them more.
So let’s show them some love, and create a living map of gratitude from every corner of Britain.
Click HERE to drop a heart on the map, and show you appreciate the efforts undertaken daily in the NHS.
Thanks a million, NHS workers - we love you.
If you have some information you can contact us by following our Twitter feed @northwaleslive - the official North Wales Live account - real news in real time.
Or like facebook.com/northwaleslive/ - your must-see news, features, videos and pictures throughout the day from the North Wales Live.
Don't forget you can also keep up to date with the latest via the free North Wales Live app.
Download it for Apple devices here and Android devices here.
Join us in showing your support and sending a heart to the NHS heroes where you live by visiting the thanksamillionsnhs website
Donald Trump's suggestion people could be injected with coronavirus as a cure denounced
During a briefing the US President noted researchers were also looking at the effects of disinfectants on the virus and wondered aloud if they could be injected into people, saying the virus “does a tremendous number on the lungs, so it would be interesting to check that”.
But William Bryan of the Department of Homeland Security said said there was no consideration of that.
Mr Bryan also said there are “emerging results” from new research that suggest solar light has a powerful effect in killing the virus on surfaces and in the air.
Past studies have not found good evidence that the warmer temperatures and higher humidity of spring and summer will help diminish the spread of the virus.
Other doctors have warned the public against injecting disinfectant or using UV light.
New lockdown rules issued for Wales by Welsh Government
The rules have been revised to continue to prevent the spread of the coronavirus.
Signing in
Good morning. I’ll be providing live updates on the coronavirus throughout the morning and afternoon. Steve Bagnall.
Conwy Castle lights up in tribute of NHS
Amazing.
