Last updated: August 27, 2025
In January, the average temperature in Mountain Ash, United Kingdom hovers around 4°C (40°F). While you can expect temperatures to dip to a minimum of -6°C (22°F), they can also rise to a pleasant 13°C (55°F). During this month, precipitation is likely, with about 82 mm (3.2 in) falling over 12 days. Notably, the average humidity is a high 88%, making it an impressively moist time of year!
In January in Mountain Ash, the average temperature is 4°C (40°F), with maximums reaching 13°C (55°F) and minimums dropping as low as -6°C (22°F). Be prepared for chilly days and pack warm clothing if you're planning to visit during this time.
In Mountain Ash in January, the precipitation amount is 82 mm (3.2 in) occurring over a span of 12 days.
In Mountain Ash in January, humidity is 88%. With an average temperature of 4°C (40°F), this humidity feels like a damp chill that seeps into your bones, making outdoor exploration less enjoyable and prompting you to seek cozy indoor activities instead.
In Mountain Ash in January, the maximum UV index is 1, which corresponds to a low Exposure Category. This means you have a time to burn of 45 minutes. For more details, you can check the Hourly UV Index in Mountain Ash.
UV Risk Categories
Weather in Mountain Ash varies notably across the year, with each month offering distinct climate conditions. This page compares January’s weather to other months in Mountain Ash, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | 4°C (40°F) | 82 mm (3.2 inches) | 88% | low |
| February Weather | 5°C (42°F) | 124 mm (4.9 inches) | 88% | low |
| March Weather | 6°C (43°F) | 111 mm (4.4 inches) | 86% | moderate |
| April Weather | 8°C (47°F) | 64 mm (2.5 inches) | 84% | high |
| May Weather | 11°C (52°F) | 93 mm (3.7 inches) | 80% | high |
| June Weather | 14°C (58°F) | 91 mm (3.6 inches) | 80% | very high |
| July Weather | 16°C (61°F) | 93 mm (3.7 inches) | 70% | very high |
| August Weather | 15°C (60°F) | 114 mm (4.5 inches) | 73% | high |
| September Weather | 13°C (56°F) | 92 mm (3.6 inches) | 79% | high |
| October Weather | 10°C (51°F) | 143 mm (5.6 inches) | 89% | moderate |
| November Weather | 7°C (45°F) | 117 mm (4.6 inches) | 90% | low |
| December Weather | 6°C (43°F) | 144 mm (5.7 inches) | 89% | low |