Frequent showers are forecast for Monday, but temperatures will remain in the high teens, peaking at around 17C.
According to Met Office Meteorologist Becky Mitchell, there is potential for thunder and lightening.
“It’s a tricky one to predict for thunderstorms for Northern Ireland in the next 24 hours,” she said.
“We’ll potentially see some thundery showers on Monday morning.
“But it might just be that they are just heavy showers with rain and no thunder.
“Those showers will quite quickly clear through the morning.
“Then Monday afternoon should be drier… after that is when things start to warm up quite a bit.”
The mercury will begin to rise from Tuesday, which is predicted to be the warmest day of the year, with potential for even higher temperatures on Thursday.
Ms Mitchell said both days have the potential to see highs above 24C — slightly warmer than the hottest day which was recorded on April 30.
“We’ve got some fairly warm weather coming up as we head through the next few days,” she said.
“We could potentially be close to the warmest day of the year so far, as we head through this week.
“There will be heavy rain on Sunday night throughout parts of north and east.
“That might linger for a while on Monday morning as well.
“There will be patchy rain to start off with, with fairly cloudy skies. Temperatures for Monday look to be around 20C,” said the Met Office spokeswoman.
The drop in temperatures on Monday only marks a brief pause in the sunny spell which saw the mercury hit 20.7C in Castlederg, Co Tyrone, on Friday.
Erin (6) and her sister Alannah (3) enjoying the sunny weather at Helen’s Bay beach on May 11, 2025 (Luke Jervis/Belfast Telegraph)
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Wednesday will see highs of 20C with minimal cloud cover and light breezes, and the trend is expected to continue throughout the rest of the week.
“From Tuesday to Friday, we’ll have, by the looks of things, dry, sunny, very warm weather each day,” Ms Mitchell said.
“Temperatures will probably be highest on Tuesday and Thursday.
“We could reach to around 24C on both days. It gets close to the highest this year.
“We could definitely get around that or a little but above. We could potentially see the warmest spell of the year so far.”