It might have officially been autumn since the start of September, but it is not going to feel like it until next week.
Temperatures, which have been between three and six degrees warmer than the average for this time of year, could drop by as much as 10 degrees between this weekend and the middle of the week.
Read more: All the latest weather in Wales stories here.
An area of low pressure is expected to bring heavy rain and high winds to most parts of Wales overnight on Sunday, heralding the start of a colder period of weather.
Met Office charts show that temperatures in Wrexham could be 22°C on Saturday, and 12°C by the middle of the week.
Forecaster Matt Taylor says: "It is unusually warm for this stage in September with temperatures well above what they should be.
"Saturday is going to be a day of above average temperatures, but fast forward to next week and the blues are going to be in the chart with temperatures colder than average. It is going to start to feel like autumn at long last.
"There are signs of changes waiting in the wings on Sunday that will bring the change from summer to autumn. The weather front will slowly push into Ireland through Sunday. It will work its way eastwards through Sunday night with gusty winds. Plenty of showers in the west on Monday, some will be heavy and thundery
As we go into the middle part of the week a big area of low pressure will throw up some longer spells of rain and strong winds. It is also going to feel substantially cooler than it does this weekend."
The Met Office long-term forecast for the UK for Wednesday, September 29, to Friday, October 8, says: "T his period will see unsettled conditions for many with low pressure systems crossing the UK. This will bring organised bands of rain, heavy at times for those in northern and western pa
"rts of the country, and interspersed with cooler and showery periods, as well as some bright skies at times. Drier and more settled conditions are likely across southern and eastern parts of the country, but there is still a chance that bands of rain and strong winds from the north and west could extend into these areas.
"The temperatures are most likely to be slightly below average for this time of the year during the start of the period but will gradually return to near average."
Here is the Met Office five day forecast for Wales:
Saturday:
Early low cloud, mist and hill fog gradually lifting to allow some bright or warm sunny spells to develop by the afternoon. Staying cloudy in the north with patchy light rain and drizzle on hills. Light winds. Maximum temperature 21 °C.
Tonight:
Rather cloudy, misty and murky overnight, with some hill fog. Some patchy light rain and drizzle at times, mainly on hills. Another mild night, with light winds. Minimum temperature 13 °C.
Sunday:
Early low cloud, mist and hill fog gradually lifting to allow some warm sunny spells to develop for many. A band of rain, locally heavy and gusty winds arriving overnight. Maximum temperature 19 °C.
Outlook for Monday to Wednesday:
Early heavy rain quickly clearing to leave sunny spells and scattered, heavy and possibly thundery showers Monday and Tuesday. Drier and brighter Wednesday. Feeling much cooler and fresher. Windy too.
To get the latest email updates from WalesOnline straight to your inbox click here.
