Other facts from our historical weather data: Which is the warmest month in Llanarmon Dyffryn-Ceiriog? July has an average maximum temperature of 20°C (68°F) and is the warmest month of the year. Which is the coldest month in Llanarmon Dyffryn-Ceiriog? The coldest month is February with an average maximum temperature of 8°C (46°F). Which is the wettest month in Llanarmon Dyffryn-Ceiriog? December tops the wettest month list with 91mm (3.6 in) of rainfall. Which is the driest month in Llanarmon Dyffryn-Ceiriog? March is the driest month with 71mm (2.8 in) of precipitation. Which is the sunniest month in Llanarmon Dyffryn-Ceiriog? May is the sunniest month with an average of 169 hours of sunshine. No idea where to travel to this year? We have a tool that recommends destinations based on your ideal conditions. Find out where to go with our weather planner.