Town CLIMATE RISK

Monmouth Flood Risk Data

Monmouth is a town, within the Monmouthshire council area. LocalRisk has flood, heat, air and ground-stability data for 544 postcodes in Monmouth; 12 samples are linked at the foot of this page.

1.7% of postcodes in Monmouth fall into Natural Resources Wales's high flood-risk band - below the UK average of about 7%. The band reflects the highest flood risk within each postcode; some properties may face little or no direct flood risk. A further 1.3% sit in the medium band; 97.0% are lower-risk. Two postcodes a few streets apart can land in different bands; what drives the gap is elevation, distance to the nearest watercourse, and how the surrounding drainage performs in heavy rain. The postcode list at the foot of this page links to the full address-level reading for each postcode in Monmouth.

Met Office UKCP18 projections (50th percentile) estimate around 24 days above 25°C per year across the Monmouthshire area, averaged over the 2021-2040 period under the RCP8.5 high emissions scenario. These are probabilistic projections - the 50th percentile is the central estimate within RCP8.5; the full range of modelled outcomes is wide and lower emissions scenarios would produce lower figures. Heat exposure within Monmouth itself is uneven: top-floor flats, west-facing terraces and properties without through-ventilation hold heat well into the night, while ground-floor homes near tree cover or open ground cool faster. The headline 24-day figure is a council-level UKCP18 estimate (LAD resolution), not a property-level reading.

Annual mean PM2.5 across the Monmouthshire area is 5.4 µg/m³ - close to the World Health Organisation guideline of 5 µg/m³. Within Monmouth, readings are not flat: postcodes within 200 metres of an A-road or major junction routinely run 30-50% higher during weekday rush hours than residential streets two roads back. The figure is a council-level Defra UK-AIR estimate (1km modelled grid).

Ground stability in Monmouth follows the underlying geology more than the postal boundary. The British Geological Survey GeoSure dataset maps clay shrink-swell risk on a 50-metre cell, and properties on the same street can sit in different bands where a clay seam ends mid-road. Pre-1980 housing on clay-rich ground is the most exposed; properties on bedrock or well-drained sandy soils are typically lower-risk. A postcode-level check picks up that variation.

A free postcode check on LocalRisk covers up to six hazards for any address in Monmouth: NRW flood mapping, BGS ground stability, Met Office heat projections, Defra PM2.5, plus coastal erosion and green-space access where relevant. The postcode list below opens an address-level report for each postcode in Monmouth; the council link at the top of this page returns to the wider Monmouthshire picture.