Last updated: August 23, 2025
In December, the average temperature in Johnstown, Ireland hovers around 6°C (43°F), with minimums dipping to -4°C (25°F) and maximums climbing to 13°C (56°F). Expect precipitation of about 90 mm (3.5 in) spread over 15 days, contributing to a high average humidity of 84%.
In December in Johnstown, the average temperature is 6°C (43°F). Maximums can reach 13°C (56°F), while minimums can drop as low as -4°C (25°F). Be prepared for chilly weather and pack accordingly if you're planning to travel during this time.
In Johnstown in December, the total precipitation amount is 90 mm (3.5 in), which occurs over a span of 15 days.
In Johnstown in December, humidity is 84%. With an average temperature of 6°C (43°F), this humidity feels like a damp chill that penetrates your clothing, making outdoor excursions uncomfortable and prompting travelers to seek refuge indoors or find warm, sheltered spots to enjoy their surroundings.
In Johnstown in December, 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 Johnstown.
UV Risk Categories
Weather in Johnstown varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in Johnstown, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | 5°C (42°F) | 55 mm (2.2 inches) | 85% | low |
| February Weather | 6°C (43°F) | 79 mm (3.1 inches) | 86% | low |
| March Weather | 7°C (44°F) | 81 mm (3.2 inches) | 86% | moderate |
| April Weather | 8°C (47°F) | 51 mm (2.0 inches) | 85% | moderate |
| May Weather | 11°C (53°F) | 72 mm (2.8 inches) | 83% | high |
| June Weather | 14°C (58°F) | 73 mm (2.9 inches) | 85% | very high |
| July Weather | 16°C (61°F) | 77 mm (3.0 inches) | 86% | very high |
| August Weather | 15°C (60°F) | 94 mm (3.7 inches) | 85% | high |
| September Weather | 13°C (56°F) | 68 mm (2.7 inches) | 86% | moderate |
| October Weather | 10°C (51°F) | 82 mm (3.2 inches) | 87% | moderate |
| November Weather | 7°C (46°F) | 88 mm (3.5 inches) | 86% | low |
| December Weather | 6°C (43°F) | 90 mm (3.5 inches) | 84% | low |