January–June

• 1 January – Welsh people honoured by The Queen in the 2010 New Year Honours List include Menna Richards, Director of BBC Cymru Wales (OBE) and banker Dyfrig John (CBE).^[1]
• 6 January – School closures and icy road conditions result from heavy snow in most areas of Wales.^[2]
• 7 January – A report issued by the Ministry of Defence concludes that the two RAF pilots involved in the Porthcawl mid-air collision over Kenfig in March 2009 "did not see each other".^[3]
• 11 January – The HM Land Registry office in Swansea (High Street) closes as a result of the Land Registration (Proper Office) Order 2009. The Wales Office of the Land Registry, situated in Llansamlet, Swansea, remains open.^[4]
• 12 January – Further heavy snow hits south and west Wales, as local authorities begin to run out of grit to treat roads.^[5]
• 12 February – Welsh Secretary Peter Hain and Assembly Environment Minister Jane Davidson announce plans to make the M4 in Wales a "hydrogen highway", with alternative energy refuelling points.^[6]
• 5 February – Dame Tanni Grey-Thompson is recommended by the House of Lords Appointments Commission as one of four new non-party-political peers.^[7]

Baroness Grey-Thompson

• 14 February – Welsh rugby international Andy Powell is arrested near Junction 33 on the M4 motorway at 0600 GMT 14 February 2010, in possession of a stolen golf buggy.^[8]
• 15 February – For behaviour "contrary to the squad's code of conduct", Andy Powell is removed from Wales' 35-man training squad for the 2010 Six Nations Championship.^[9]
• 1 March – A BBC poll suggests that support has risen for full law-making powers for the Welsh Assembly, up to 56%, with 35% against, although Nick Bourne the leader of the Welsh Conservative Party (who supported a yes vote) is sceptical of the poll results.^[10]
• 16 March – Welsh Slate announces the closure of Oakeley Quarry at Blaenau Ffestiniog.^[11]
• 17 March – Government figures show that the unemployment rate in Wales, at 9.2% is higher than any other home country and higher than all but two other regions of the UK.^[12]
• 18 March – The Marriage (Wales) Act 2010 brings the Church in Wales's marriage regulations into line with those of the Church of England.^[13]
• 16 April – Four men are killed and a fifth is seriously injured in a car crash near Porthcawl.^[14]
• 6 May – In the United Kingdom general election, the Conservative Party wins 8 seats, Labour 26, Plaid Cymru 3 and the Lib Democrats 3.
• 12 May – Cheryl Gillan is confirmed as Secretary of State for Wales in the new UK government of David Cameron; she is the first woman to hold the post.^[15]

Cheryl Gillan

• 25 May – The Learned Society of Wales is launched.^[16]
• 28 May – Llanrwst celebrates the 400th anniversary of the almshouses built by Sir John Wynn, 1st Baronet.
• 15 June – Cheryl Gillan, the new Welsh Secretary in the Conservative—Liberal Democrat coalition government at Westminster, announces that the 2011 Welsh devolution referendum will probably be held between January and March 2011.^[17]
• 16 June – New members of the Gorsedd are announced by the National Eisteddfod of Wales. They include Tim Rhys-Evans, Edwin Regan and Jill Evans.^[18]
• 23 June – A Danish tabloid newspaper accuses Stephen Kinnock, who is married to Danish politician Helle Thorning-Schmidt, of tax evasion.^[19]
• 24 June – Barry-born Julia Gillard becomes Australia's first female prime minister.
• 28 June – The Archbishop of Canterbury, Rowan Williams, unveils a new memorial on the site of Six Bells Colliery. The sculpture, Guardian (of the Valleys) by Sebastien Boyesen, commemorates the pit disaster of 1960 and is a tribute to those who work in dangerous industries.^[20]

The Guardian of the Valleys

July–December

• 1 July – Wales's four archaeological trusts launch an online searchable website, known as Archwilio, at the Treftadaeth Conference in Swansea. Alun Ffred Jones AM, Minister for Heritage, observes: "Wales is the first country in Britain that has made all its archaeological records available online" and "Archwilio will be a tremendous asset not only for the people of Wales but also for those further afield who have an interest in the rich archaeology and cultural heritage of our country".^[21]
• 5 August – The Faenol Festival is cancelled for the second year running.^[22]
• 23 August – The remains of Anglesey-born MI6 worker Gareth Williams are discovered locked in a sports bag^[23] at his Pimlico flat.^[24]
• 29 August – Air-sea rescue services begin a frantic search for missing kayaker Elizabeth Ashbee, who became separated from four colleagues in rough waters and bad weather at Ynys Feurig near Rhosneigr, Anglesey. Her body is found in Caernarfon Bay two days later.^[25]
• September – The University of Wales Trinity Saint David, created by the merger of Trinity University College and the University of Wales, Lampeter, admits its first students.
• 5 September – Holly Stuckey, a pupil at Ysgol Maesteg School, is taken to hospital suffering from an allergic reaction, but dies shortly afterwards. Her parents later claim she was severely bullied at the school.^[26]
• 13 September – Archaeologists working at Caerleon announce the discovery of a suit of Roman armour.^[27]
• 22 September – Sainsbury's original Newport store closes and a new superstore opens in Crindau.
• 4 November – The accident report on the Porthcawl mid-air collision over Kenfig of March 2009 is released.^[28] The AAIB makes no safety recommendations, referring instead to the recommendations made in January's Ministry of Defence inquiry report.
• 16 November – Buckingham Palace confirms that Prince William of Wales will marry Catherine Middleton in 2011. Her title following the marriage would be dependent on whether an additional title were conferred on the prince.
• 19 November – The Welsh Pony and Cob Society opens a museum at its new headquarters near Felinfach.^[29]
• 28 December – Andrew Craig, of Caernarfon, completes the challenge of climbing Snowdon every week for a year, thus earning £15000 for charity.^[30]

Undated

• Both major chemical production plants at Cefn Mawr shut down.

Awards

• Glyndŵr Award – David Nash
• National Eisteddfod of Wales: Chair – Tudur Hallam
• National Eisteddfod of Wales: Crown – Glenys Mair Glyn Roberts
• National Eisteddfod of Wales: Drama Medal – withheld
• National Eisteddfod of Wales: Prose Medal – Jerry Hunter
• Gwobr Goffa Daniel Owen – Grace Roberts
• Wales Book of the Year:
  • English language: Philip Gross – I Spy Pinhole Eye
  • Welsh language: John Davies – Cymru: Y 100 lle i’w gweld cyn marw
• Dylan Thomas Prize: Elyse Fenton – Clamor^[35]
• Kyffin Art Prize:

New books

Music

English-language

• Rhys Ifans plays the title role in Mr. Nice, as Howard Marks.
• Patagonia, starring Matthew Rhys
• Michael Sheen stars in Unthinkable
• Third Star, set in Pembrokeshire

Welsh-language

• Patagonia

Welsh-language television

• Only Men Aloud
• Rhestr Nadolig Wil

English-language television

• Hidden Houses of Wales (with Laurence Llewelyn-Bowen)
• Rhod Gilbert's Work Experience
• Sherlock, produced by BBC Wales
• The Special Relationship (TV film) starring Michael Sheen as Tony Blair.
• Snowdonia 1890