Last updated: August 23, 2025
In May, the average temperature in St Johnston, Ireland hovers around 11°C (52°F), with a minimum dipping to 0°C (32°F) and a maximum peaking at 25°C (78°F). Expect about 93 mm (3.7 in) of precipitation spread over 16 days, contributing to an average humidity of 83%. Prepare for a wet and mild month!
In May in St Johnston, the average temperature is 11°C (52°F). The maximum can reach 25°C (78°F), and the minimum can be as low as 0°C (32°F). This diverse range of temperatures makes it an ideal time for travelers to enjoy both outdoor activities and cozy indoor experiences.
In St Johnston in May, the precipitation amount is 93 mm (3.7 in) spread over the course of 16 days.
In St Johnston in May humidity is 83%. With an average temperature of 11°C (52°F), this humidity feels like a damp chill that can make outdoor activities uncomfortable, often leading travelers to seek shelter indoors or to dress in layered clothing to stay warm while exploring the area.
In St Johnston in May, the maximum UV index is 6, which corresponds to a high Exposure Category. The time to burn is approximately 25 minutes. To find the hourly UV index in St Johnston, you can refer to this Hourly UV Index in St Johnston.
UV Risk Categories
Weather in St Johnston varies notably across the year, with each month offering distinct climate conditions. This page compares May’s weather to other months in St Johnston, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | 5°C (42°F) | 72 mm (2.8 inches) | 84% | low |
| February Weather | 6°C (42°F) | 113 mm (4.4 inches) | 84% | low |
| March Weather | 6°C (44°F) | 106 mm (4.2 inches) | 83% | moderate |
| April Weather | 8°C (47°F) | 64 mm (2.5 inches) | 84% | moderate |
| May Weather | 11°C (52°F) | 93 mm (3.7 inches) | 83% | high |
| June Weather | 13°C (56°F) | 107 mm (4.2 inches) | 83% | very high |
| July Weather | 15°C (59°F) | 99 mm (3.9 inches) | 86% | very high |
| August Weather | 15°C (58°F) | 157 mm (6.2 inches) | 86% | high |
| September Weather | 13°C (55°F) | 97 mm (3.8 inches) | 87% | moderate |
| October Weather | 10°C (50°F) | 112 mm (4.4 inches) | 87% | moderate |
| November Weather | 7°C (46°F) | 94 mm (3.7 inches) | 88% | low |
| December Weather | 6°C (43°F) | 103 mm (4.1 inches) | 84% | low |