Tuesday's top temperature of 21C was recorded in Castlederg, Co Tyrone.
Last Wednesday previously held the record for 2013 so far, when 20.7C was recorded at Stormont.
According to the Met Office, it should be "remaining fine throughout with further warm sunny spells" across Friday, Saturday and Sunday.
And even into the start of next week is looking "largely fine with sunny periods".
But the questions remains whether the summer months will also deliver when it comes to sunshine.
There are currently indications that conditions may be rather changeable through the rest of June and into early July," forecasters say of the UK-wide picture.
"Temperatures are likely to be near, or a little below average for the time of year.
"This is partly as a result of having unseasonably cool sea surface temperatures for the time of year surrounding the United Kingdom."
If you've been out enjoying the sun, you can send your snaps to be featured in our gallery!