Cardiff Temperature by Month

Cardiff, Wales, United Kingdom has an average annual maximum temperature of 14°C (57°F), ranging from 9°C (48°F) in January to 20°C (68°F) in August. Below you'll find a full monthly breakdown and a comparison with cities worldwide.

Visitors to Cardiff can expect significant temperature changes throughout the year. Nighttime temperatures also vary widely, ranging from 14°C (57°F) in August to 4°C (39°F) in January.

The chart below illustrates the average maximum day and minimum night temperatures in Cardiff by month:

The coolest part of the day is typically between 4 AM and 6 AM, while 3 PM is usually the warmest, when solar heating is at its peak. August, the city's warmest month, averages 184 hours of sunshine.

The chart below shows the average temperature throughout the year:

Cardiff's average annual maximum temperature is 14°C (57°F). To put that in context, here's how it compares to a few well-known destinations:

Barcelona, Spain has an annual average of around 21°C (70°F), with warm summers and mild, fairly short winters.

Interlaken, Switzerland averages 8°C (46°F) a year, with cold winters and cool summers thanks to its Alpine setting.

Buenos Aires, Argentina averages 23°C (73°F) a year, with hot summers and mild winters, and seasons reversed compared to Europe.

Tokyo, Japan averages 21°C (70°F) a year, with hot summers, cool winters, and a well-defined cherry blossom spring.

Temperature alone doesn't tell the whole story, humidity plays a big role in how warm or cold it actually feels. High humidity in summer makes the heat feel more intense, particularly once temperatures climb above 25°C. In winter, the same humidity can make cold air feel sharper than the thermometer suggests.

In the cooler months, when temperatures drop below 10°C, high humidity makes the cold feel more cutting than it would in dry conditions.

In Cardiff, January is the coolest month, with average highs of 9°C (48°F) and humidity around 89%, considered very high. For a full picture, see our humidity page.

Climate temperature data is typically calculated as a 30-year average. This smooths out year-to-year variability and gives a more reliable picture of what a place is actually like, rather than what happened in any single unusual year.

The readings come from a range of sources, land-based weather stations, ocean buoys, ships, and satellites. That data is collected by weather services around the world, then pooled, quality-checked, and averaged to produce the climate records you see here.

For cities and regions with significant elevation, altitude is one of the biggest factors shaping local temperatures. As a rule of thumb, temperatures fall by around 6°C for every 1,000 metres gained, so a city at 2,000 metres will typically be around 12°C cooler than a city at sea level in the same region. Higher ground also tends to see more dramatic day-to-night temperature swings, since thinner air loses heat faster after sunset.

For more on Cardiff's weather, including monthly rainfall, sunshine hours, and humidity, visit our Cardiff climate page.