THE IRISH WEATHER has been somewhat erratic of late but the major change blowing our way this week is a welcome sight for most – especially after seeing our wettest April in 14 years.

Temperatures are expected to rise to balmy heights of 20 degrees Celsius today with periods of prolonged sunshine in Leinster and parts of Ulster, according to Karl Mehlhorn of the Irish Weather Network.

There will be lower temperatures of 13 to 15 degrees Celsius in the west and south due to onshore wind and cloud. There will also be a continuing risk of light rain and drizzle for now (sorry).

The whole country will be more on par tomorrow with sunshine expected everywhere. Some lingering cloud will eventually be pushed back by late Wednesday in the far west and southwest. Typically, it will be dry and warm with temperatures ranging from 19 to 21 degrees in most places. The midlands will see the warmest spells.

Thursday looks set to be glorious everywhere, says Mehlhorn, with good amount of sunshine as the winds will swing into the south east and remain light.

Continuing to creep upwards, temperatures of 20 to 22 degrees Celsius are widely expected with some spots even making it to 23 degrees. There may be some exceptional showers but it will largely remain dry. Sea breeze will be set off around the coasts holding the temperatures closer to 16 or 17C during the afternoon.

And then on Friday

Friday looks set to be the warmest day of the lot with unbroken sunshine at first and temperatures rising to as high as 24C. On the east coast, temperatures will stay at a more modest level of 16C.

It’s not all sunshine and ice-creams though. The west will see the highest temperatures but also some showers. A few heavy, thundery downpours are also possible over Munster in the late afternoon as high pressure from Scotland tries to stave off low pressure trying to nudge in from the south.

Mehlhorn warns that the UV index will be medium to high all week and sunburn is a real risk throughout, even under cloud cover.

What of the weekend?

Met Éireann says that Saturday and Sunday will be dry and sunny but the risk of thundery showers will still be there, especially in the south.

Temperatures will fall back slightly but still warm at 17 to 22C. Saturday will be breezy but winds will be moderate on Sunday.

We’re getting used to this weird weather, but will it continue to be SO changeable?

As Mehlhorn says, “It seems like a lifetime ago since we enjoyed that warm and sunny spell in March and then April really lived up to its nickname as showers dominated the entire month, even filtering into the first half of the month of May.”

May is usually a transition month when the last of winters residual cold is replaced by milder and moister air in the atmosphere leading us into the summer. This is what happens most of the time but in recent years, the seasons are somewhat confused.

In fact, if we did not have that warm spell in March, we may not have noticed the cold of April. Or it may not have seemed that significant.

May is usually the transition month from cold to warm and this week will see the first real mild spell of the year. There will actually be weather that Ireland is more accustomed to at this time.

Mehlhorn continues: “The month should come back in close to average, balancing out from a cold start and warm finish but bear in mind, we can still get cold weather returning in June with an incursion from the north if the synoptics favour such. If warm weather can occur in March, cold weather can reappear in June with the start of Meteorological Summer.”

Looking back to summer 2011, all three months were below average in terms of temperatures.

“There were BBQ days here and there,” says Mehlhorn, “but they were limited.”

Summer 2012? He wouldn’t bet against a cold day or two in June as the residual cold still in northern areas may drift south. Despite the sun’s rays beaming directly down on the country by 21 June, airmass still dictates temperature, Mehlhorn reminds us.

That cold threat is “all but gone” by July. August then is usually our warmest month.

Could we be lucky and skip any cold spell in June then?

Mehlhorn isn’t too optimistic.

“Prepare yourself to be disappointed would be the norm. We can only hope for a unique spell to unfold whereby heat and sun prevails for a change but hope and science are not on the same page. We can only wait and see.”

Explainer: How does weather forecasting work?

Explainer: Where did this glorious weather come from?>