A warm front is currently over Ireland which is causing night time temperatures to be unusually higher than during the day time.
Parts of the country are seeing temps as low as 7.3C currently but will get a jump towards 13C after midnight.
The national forecaster has explained that this phenomenon depends on when the front passes through.
A Met Eireann forecaster said: "A warm front is moving over Ireland today. Depending on the time of frontal passage, this can result in daytime temperatures being lower than night-time temperatures. See below air temperatures observed at noon today and the forecast temperatures for midnight tonight."
It comes ahead of what is expected to be a horrid week with rain and wind dominating.
The forecaster added: "Low cloud with drizzle and mist through tonight, particularly noticeable along coasts and on hills and mountains, with more persistent rain at times on the northwest coast. Temperatures overnight of 10 to 12 degrees while southwest winds will remain mostly fresh.
"Tuesday will be cloudy with patchy rain and drizzle, especially along west facing coasts. Temperatures will be between 12 and 15 degrees, with fresh and blustery southerly breezes.
"Remaining unsettled over the coming days, with cooler conditions developing from midweek."
