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Live forecasts update automatically; written guidance last reviewed 20 June 2026 by the Civic Affairs weather desk. Data from national met services via Open-Meteo.
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The weather in Saint Mellons today, as shown in the live forecast above, is typical for this Cardiff suburb, with conditions often influenced by its proximity to the Bristol Channel. Expect a mix of cloud and clear spells, with temperatures in line with the seasonal average for late spring.
What is the typical climate for Saint Mellons?
Saint Mellons experiences a temperate maritime climate, meaning mild winters and cool summers with rainfall spread fairly evenly throughout the year. The area is slightly sheltered compared to more exposed coastal parts of South Wales, but it can still see brisk winds from the west or southwest. Frosts are less common here than in inland valleys, and summer temperatures rarely exceed the mid-20s Celsius.
How does the local geography affect the forecast?
Being on the eastern edge of Cardiff, Saint Mellons sits on relatively low-lying ground near the River Rhymney. This can lead to mist or low cloud forming on calm, clear nights, especially in autumn and winter. The nearby Bristol Channel also moderates temperature extremes, keeping winter nights milder and summer days slightly cooler than areas further inland.
Is Saint Mellons likely to get snow in winter?
Snowfall is infrequent and usually light, as the mild maritime air from the Bristol Channel often keeps temperatures just above freezing. Significant snow accumulations occur only once every few years, typically when cold easterly winds arrive.
Does Saint Mellons flood often?
The area near the River Rhymney can be at risk of fluvial flooding after prolonged heavy rain. However, most of the residential areas are on higher ground, and flood defences have been improved in recent years to reduce the risk.
When is the best time to visit Saint Mellons for good weather?
Late spring (May to June) and early autumn (September) offer the most reliable balance of mild temperatures, longer daylight hours, and lower rainfall. July and August can be warmer but are also the wettest months on average.
For more local details, explore our UK weather hub or check the 10 day weather forecast UK for the wider region. You can also compare conditions with nearby Bristol Weather.