LL36 0AD - Flood, Heat, Air & Subsidence Risk - Tywyn

Gwynedd, Tywyn

LL36 0AD in Tywyn has a High flood risk. Heat risk is Lower, with a median (50th percentile) of 8 days above 25°C per year, averaged over the 2021-2040 period under the RCP8.5 high emissions scenario (Met Office UKCP18). Air quality is Low at PM2.5 4.3 μg/m³, within the WHO annual guideline of 5 μg/m³ (Defra UK-AIR). Ground conditions are Low risk, with Riverine Clay And Floodplain Sands And Gravel geology; shrink-swell risk is classed as improbable (BGS GeoSure).

• Flood: Plan with flood risk in mind for this area.
• Heat: Projected 8 days above 25°C per year, 2021-2040 average (Met Office UKCP18, 50th percentile under RCP8.5).
• Air quality: PM2.5 4.3 µg/m³ - within the WHO annual guideline of 5 µg/m³ (Defra UK-AIR).
• Ground: BGS data: Riverine Clay And Floodplain Sands And Gravel geology. Shrink-swell risk classed as improbable (British Geological Survey).
• Coastal erosion: NCERM data: coastal erosion zone 8m from this postcode. Erosion risk: high.

Flood risk at LL36 0AD is rated High, based on Natural Resources Wales flood mapping.

Air quality at LL36 0AD is rated Low, based on Defra UK-AIR annual mean PM2.5 data. Fine particulate matter (PM2.5) comes primarily from road traffic, industry, and domestic burning. Long-term exposure above the WHO guideline of 5 µg/m³ is linked to respiratory and cardiovascular health risks. Buyers and renters in higher air quality risk areas may wish to consider whether the property is near busy roads or industrial sources.

BGS GeoSure data classes the underlying soil at LL36 0AD as Riverine Clay And Floodplain Sands And Gravel, with shrink-swell hazard rated improbable (subsidence risk band: Low). Soil type and shrink-swell behaviour drive subsidence claims following dry summers; recent ABI data shows insurer payouts rose sharply after the 2022 and 2025 hot summers. A structural survey is the reliable way to assess ground risk for a specific property.

The nearest projected coastal erosion zone to LL36 0AD is 8 m away (NRW NCERM No Active Intervention - Medium-term (2025-2055) mapping) and the postcode is in the high coastal erosion risk band. Coastal erosion risk varies along the shoreline depending on local geology, sea defences and Shoreline Management Plan policy. For properties near the coast, a specialist coastal erosion risk assessment is recommended.

This LocalRisk report for LL36 0AD draws on four official UK open data sources: Natural Resources Wales flood mapping, Met Office UKCP18 climate projections, Defra UK-AIR PM2.5 monitoring, and British Geological Survey GeoSure subsidence mapping. Risk ratings are a screening tool, complementing - not replacing - the searches and surveys ordered as part of a property transaction. Data covers Gwynedd and is updated as new official datasets are published.

Gwynedd has a predominantly upland and coastal setting with mountains, river valleys and dispersed settlements and experiences cool, wet winters and mild summers, shaped by Atlantic weather and steep catchments.

Natural Resources Wales flood zone data places LL36 0AD in the high flood risk band. The band reflects the highest flood risk within the postcode; some properties within this postcode may face little or no direct flood risk. A formal flood risk search and review of buildings insurance availability is recommended before any property transaction in this area.

Practical check: In a coastal flood risk area - ask about tidal flooding history and check the property's elevation relative to sea level. The nearest projected erosion zone is 8m away - check the Shoreline Management Plan policy for this stretch and whether the property is within 100 years of the erosion line. These are postcode-level indicators - conditions vary between individual properties.