Met Éireann said temperatures will continue to climb over the weekend with warm or very warm conditions in many places.
The national forecaster said high pressure will bring mostly dry and settled conditions, but there may be sea fog in some coastal areas.
Today (Friday, May 22), will be a mild and cloudy day initially with mist and drizzle across the country.
Some showery rain will spread eastwards later in the day, with heavy falls in Ulster, light and patchy showers elsewhere.
Some hazy sunny spells will develop later, feeling warm with highest temperatures of 17° to 20°C in moderate southerly breezes.
It will be a bit cooler in southern coastal areas due to sea fog.
Showers will die out tonight, leaving a dry and cloudy night with mist and fog, particularly in the south-east. Overnight lows of 9° to 12° with light south-west or variable breezes.
Saturday will be a dry day with warm sunny spells and moderate south-west breezes. Afternoon temperatures will reach highs of 17° to 21° generally, a little cooler in some coastal areas.
Most areas will remain dry and clear on Saturday night, cloud will continue to build in the northwest.
Some mist and fog patches will form in the south-west in light or variable southerly breezes. Lowest temperatures of 8° to 12°.
Sunday will be another warm day with sunny spells, cloudier in the north-west until evening when brighter conditions are expected.
Highest temperatures of 18° to 22° with light southerly or variable breezes.
Sunday night will be clear and dry night with patches of mist, fog and sea fog forming towards morning. Light or variable southerly breezes with lowest temperatures of 9° to 12°.
Monday will bring bright and sunny conditions to most parts, cloudier for a time in the north-west. Highest temperatures of 18° to 23° in light variable breezes.
Tuesday will see warm and sunny spells becoming widespread, but mist and fog patches may linger in places for a time.
Met Éireann said rainfall amounts over the next week are expected to be significantly below average for most areas.
Less than around 10mm is forecast for all areas, with close to no rainfall forecast for some parts of the east.
Mean air temperatures for the coming week will be possibly up to 4°or 5° above average in places, ranging from 13° to 16°.
Mean soil temperatures have been up to 1.4° above average during the past week, and are expected to further increase during the coming seven days.
With dry weather expected from Saturday and temperatures rising, drying conditions should improve, but light winds may limit them to moderate.
There will be good opportunities from spraying from the weekend onwards.
Soil moisture deficits are expected to increase for all soil types for the coming week, increasing to between 10mm and 66mm, the highest deficits in the east.
The outlook shows that field trafficability will increase, but there will be some restriction to growth.
Met Éireann has also issued a potato blight advisory as weather conditions conducive to the spread of the disease persist until Sunday.