The temperature in Derry on Tuesday is predicted to reach as high as 24°C, according to the Met Office.
The Met Office forecasts full sun from 6am to 6pm on Tuesday.
The sun will be at its strongest from 1pm to 3pm when the UV Index is predicted to rise to seven which means there is a high risk of harm from unprotected sun exposure.
The outlook for the rest of the North on Tuesday "is another generally dry bright and very warm day with some sunny spells. Some cloud arriving later in the afternoon, with a chance of the odd isolated shower. Maximum temperature 25 °C," reads the weather forecast on MetOffice.gov.uk
The warm weather is not predicted to last with showers and temperatures in the mid-teens forecast on Wednesday and Thursday.
Met Éireann is predicting similar temperatures and weather fronts for Co. Donegal.