The temperature in Derry looks set to plummet this weekend as chilly Polar air moves in from the North, according to the Met Office.
Some parts of the North West could see a drop of between five and 10°C by Saturday.
The temperature in Derry on Tuesday was approximately 20°C but it could drop to as low as 8°C on Saturday.
The change in the temperature looks set to start on Wednesday and last through the weekend.
But don't write off summer just yet.
Experts predict that warm and dry weather could return to the North West by end of August and the beginning of September.
"Through the beginning and middle part of September, there is an increasing chance that much of the UK will see a good deal of dry, warm and settled weather," reads a weather update on the Met Office website.
"Northern and western areas could occasionally have wet and windy spells towards the middle part of the month, but these should be short-lived. Temperatures are likely to be generally warm across the UK, with a chance of very warm conditions developing in the south."