London construction sites are forecast to get a drier working window from Wednesday 28 October after a wet start to the week, with the Met Office currently showing dry or sunny conditions across the capital through much of Wednesday, Thursday and Friday.
The improvement follows the back-to-back passage of Storms Austen and Boelo. Monday will still begin wet and Tuesday brings another period of rain and showers, so the clearest opportunity for external work comes later in the week rather than immediately after the storms.
A crane above an active construction site in London. Drier and lighter-wind conditions are forecast to give external trades a better working window later in the week. Photo: London Construction Magazine.
Wednesday becomes the first dry working day
The Met Office forecast for London and South East England, updated on Sunday 25 October, has rain moving across the region on Monday morning before clearing northeast during the afternoon. Tuesday remains breezy with rain and showers in the morning, followed by improving conditions later in the day.
Wednesday is forecast to be dry, with winds easing during the afternoon. Thursday may begin with fog in places before sunny spells develop, accompanied by a light breeze. The Met Office's London forecast currently shows 16°C on Wednesday, 15°C on Thursday and 15°C on Friday, with sunny or partly cloudy conditions on all three days.
| Day | London forecast | Site position |
|---|---|---|
| Monday 26 October | Rain clearing during the afternoon, around 16°C | Wet start; drainage, access and exposed surfaces may need checking |
| Tuesday 27 October | Rain or showers early, improving later, around 15°C | Improving later, but morning external work remains weather exposed |
| Wednesday 28 October | Dry and sunny, winds easing, around 16°C | Best current forecast for a full external working day |
| Thursday 29 October | Possible morning fog, then sunny spells and a light breeze, around 15°C | Another favourable window once visibility improves |
| Friday 30 October | Sunny becoming partly cloudy later, around 15°C | Current London forecast remains favourable for external activity |
External trades could regain working time
A run of drier, lighter-wind conditions is useful for packages that are most exposed to short weather interruptions. Roofing, façade installation, glazing, scaffold alterations, MEWP work, external finishes and lifting operations can all lose productive time when wind or rain moves through a site during a shift.
The forecast does not set operating limits for those activities. Tower cranes, mobile cranes and access equipment have their own manufacturer requirements and lift plans, while temporary structures and work at height remain subject to site-specific conditions. A calm forecast at ground level is not a substitute for anemometer readings, equipment limits or the temporary works design.
Sites exposed to Austen or Boelo also need to deal with the condition left behind before using the better weather. LCM's construction-site checks after Storms Austen and Boelo cover scaffolds, hoardings, temporary works, cranes and excavations that may require inspection following severe wind or rainfall.
Groundworks may need Monday and Tuesday to recover
The midweek improvement will not affect every package in the same way. Groundworks, excavations and working platforms can remain wet after rainfall has stopped, particularly where temporary drainage has been carrying repeated storm water or haul routes have softened under plant movements.
Concrete, waterproofing and external finishes also depend on the condition of the substrate and the product being used, so Wednesday's dry forecast does not automatically recover time lost earlier in the week. It does, however, give site teams a better opportunity to pump out, inspect, clean down and prepare areas before later packages restart.
The change is useful after an autumn in which weather has become a live programme issue. LCM's earlier analysis of wet and windy risk for UK construction sites looked at the effect repeated rainfall can have on groundworks, crane operations, temporary structures and the amount of drying time available between weather systems.
Drier pattern could continue into early November
The improvement may extend beyond the immediate three-day window. For the period from Friday 30 October to Sunday 8 November, the Met Office expects high pressure to become more dominant near the UK after an initial band of rain moves east or weakens.
Its long-range outlook currently favours drier-than-normal conditions for most areas into early November, although cloudy periods, overnight fog and some colder nights remain possible. For London sites, Wednesday 28 October is currently the first clearly dry day in the short-range forecast, followed by sunny spells and lighter winds on Thursday.
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Founder & Author, London Construction Magazine | Construction Testing & Investigation Specialist