The Met Office has said there is scope for some rather warm days later in September, but temperatures for the period as a whole will probably be close to average.
In its long-range forecast for the UK, the forecaster said conditions will remain changeable, with occasional rain or showers arriving from the North Atlantic, most frequent across northern and western parts of the UK, where some strong winds will also be possible at times.
However, there will also be some reasonable dry and more settled periods, especially across southern areas. Later in the month, high pressure may become more dominant in the vicinity of the UK, perhaps bringing more widely settled conditions for a time, especially away from the far north.
This week's forecast
Temperatures will remain around 17C and 18C this week across Merseyside. In its outlook for Tuesday (September 8), the Met Office said: "A day of sunshine and showers, with the showers turning heavy and thundery in places. Winds also freshening once again helping to give a rather cool feel to the day. Maximum temperature 18 °C."
Looking further ahead to the end of this week, the forecaster added: "Drier and brighter on Wednesday with spells of sunshine. Another band of rain then moves in for Thursday, before drier and brighter weather returns on Friday. Temperatures likely around average."
Autumn definitions
September signals the start of autumn for many. Autumn is the transition season between summer and winter, often associated with cooler temperatures, harvest time and the gradual transformation of the landscape as leaves turn shades of yellow, orange, red and brown.
The Met Office said: "While some people consider autumn to begin on September 1, others wait until later in the month. Both approaches are correct, but they are based on different ways of defining the seasons."
Meteorological autumn consists of September, October and November, dividing the year into four fixed seasons each lasting three complete calendar months. Astronomical autumn, however, begins with the autumn equinox, which usually falls on September 22 or 23 each year. During the equinox, the sun shines directly above the Earth's equator, resulting in day and night being nearly equal in length across the globe.
Autumn weather patterns
The Met Office said the weather forecast can vary throughout autumn. The UK forecaster said: "Across the UK, autumn can bring a striking change in weather patterns. Warm spells are still possible, particularly during September, but temperatures generally begin to decline as the season progresses. At the same time, daylight hours shorten and the likelihood of wetter and windier weather increases."
Some signs that autumn has arrived include the changing colour of the leaves, a fall in temperatures and the arrival of cooler mornings.
