Tomorrow (Tuesday) will start to heat up during a sunny day with a gentle south-westerly breeze.
The temperature is due to hit 18degC.
However, on Wednesday, after some overnight mist, 20degC is expected, although there will be some light cloud.
Thursday may be a little cooler (16degC) and Friday could be back to a seasonal average of 13degC, although there should be plenty of sunshine.
For those suffering with hayfever, the pollen levels are due to be moderate during the week.