Scientists collated data from 400 variations of the climate computer model developed by the Hadley Centre, part of the Met Office.
Each variant has been checked to see how well it predicted the climate of past decades; and the numbers have been compared with projections of other computer models.
This allowed scientists to assign probabilities to various forecasts.
Using a range of online tools including a "weather generator", people will be able to enter their postcodes and see projections of how conditions are likely to change within 25 sq km grid squares at different points in the future.
But some climate scientists have reservations about trying to project the future on such a detailed scale.
"If your decisions depend on what's happening at these very fine scales of 25 km or even 5 km resolution then you probably shouldn't be making irreversible investment decisions now," commented Myles Allen of Oxford University, one of the UK's leading climate modellers.
But the idea of the impact assessment has been well received by environment groups.
"It's great that the government has decided to put together such a scientifically robust analysis of the potential impacts of climate change in the UK," said Keith Allott, head of climate change at WWF-UK.
"But the picture it paints is an alarming one,"
"This research confirms that not only is climate change already having a serious impact in Britain, but that we are also locked into further impacts, and that these impacts will get much worse unless we act now to tackle the problem."
Campaigners say that the UK impacts are likely to be minor compared to other parts of the world.
Last month a report from the Global Humanitarian Forum, the think tank chaired by former UN secretary-general Kofi Annan, said the UK was among the 12 countries likely to be least affected by climate change.
"Life in parts of the UK will get harder, but it will get a great deal harder in countries already suffering the impact of climate change," said Alison Doig, senior climate policy expert with Christian Aid.
"Their plight will worsen dramatically unless the international community wakes up to the fact that a full-blown emergency is looming."
On Friday, the Environment Agency will release an assessment of how the changing climate will affect the risk of impacts such as flooding in England and Wales.
Commenting on the UKCP09 projections, Environment Agency chairman Chris Smith said:
"These new projections remind us starkly of the choices we face in ensuring a sustainable future for our fragile planet.
"A failure to cut greenhouse gas emissions will lead to a battle for survival for mankind and many other species across the globe by the end of this century; and we will feel the effects here in the UK too."
The agency is likely to recommend measures that would protect areas of the UK, and sectors of the economy, against climate impacts such as flooding.
With hundreds of miles of roads and railways running along embankments, scientists are studying the impact of climate change on these vital structures
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