Britain is poised to experience its first 20-degree Celsius temperature of the year this week, as meteorologists predict five consecutive days of wall-to-wall sunshine in London starting today. The Met Office has issued a forecast indicating that each day will grow progressively warmer, following yesterday's high of 13C (55F).
Progressive Warming Throughout the Week
Today is expected to reach 15C (59F), with tomorrow and Thursday potentially hitting 19C (66F) or even 20C (68F). These temperatures would make the UK warmer than popular European holiday destinations such as Ibiza at 16C (61F), Corfu at 15C (59F), and Faro at 17C (63F). The Met Office forecasts sunshine in London from sunrise to sunset from today until Saturday, before cloudier conditions return on Sunday.
Potential Record-Breaking Warmth
The UK's warmest day of the year so far could occur by midweek, potentially exceeding the current 2026 high of 19.2C (66.6F) recorded at Northolt in West London on March 5. This pleasant weather is attributed to a warmer southerly wind drawing air from the Mediterranean, resulting in temperatures 6C or 7C above the seasonal average for Britain.
Vernal Equilux and Seasonal Transition
Today marks the Vernal Equilux for parts of the UK roughly south of Norwich, when daylight and darkness are closest to being exactly 12 hours each. For locations generally north of the city, this occurs tomorrow. After the Vernal Equilux, the length of days becomes longer than nights as the UK moves towards summer.
Regional Weather Variations
Yesterday brought unsettled conditions to the North, with rain gradually moving eastwards in the afternoon and turning lighter, while the South remained mostly dry. Today will begin cloudy before skies brighten with sunny spells for England and Wales, but Scotland and Northern Ireland will experience thicker cloud and further rain.
Tomorrow and Thursday are anticipated to be the best days of the week, with temperatures cooling towards the seasonal average of 16C (61F) by Friday. Met Office chief forecaster Dan Harris stated: 'Wednesday looks likely to be the warmest day of the week for many, with high pressure dominant.'
Foehn Effect and Temperature Patterns
Harris added: 'The warmest spots are likely to be in parts of west Wales and western England, where under sunny skies, 18C to 19C, possibly even 20C is on the cards. This is due to the additional boost expected from the passage of east to south-easterly winds over areas of higher ground, known as the Foehn effect.'
The Foehn effect, often observed in the Highlands, occurs when air is forced over a mountain range, warms, and moves down the other side, raising temperatures. Harris also noted: 'There'll be a big diurnal range this week, which is the difference between the maximum daytime temperature and minimum overnight temperature. Thanks to the clear skies during the day, we'll see some chilly nights after the warmer days with a few places experiencing air frost.'
Long-Range Forecast and Seasonal Context
Looking further ahead, the Met Office long-range forecast expects temperatures to remain close to or a little above average by this weekend and into next week. While most places are predicted to be predominantly dry, forecasters indicated that the odd shower is possible in the South East, and parts of the North West may also see rain.
Astronomical spring begins on Friday, following meteorological spring which started on March 1. This period of warming weather aligns with the seasonal transition, offering a welcome respite and brighter conditions across the country.
