Castlebar Weather in May
Thinking of visiting Castlebar in May? Expect moderate temperatures reaching 16°C (61°F) during the day, dropping to 8°C (46°F) at night, and note that quite a bit of rainfall is likely.
Rainfall in Castlebar in May
Rain is expected on roughly 19 days, totalling around 94 mm (3.7 in) for the month. Rain this month is fairly typical, a standard mix of wet and dry days with no particularly heavy or persistent showers.
Temperature in Castlebar in May
In May, Castlebar gets moderate temperatures, with highs of 16°C (61°F). Nights cool to around 8°C (46°F). Temperatures can feel cooler in the morning and evening, so layering is often the best approach. With overnight lows of 8°C (46°F), nights are cold. The cold air does make for deep, comfortable sleep if you have enough blankets.
Sunshine in Castlebar in May
The city usually sees around 157 hours of sunlight, indicating a moderately sunny period.Should you favor a climate that's both dry and comfortably warm, June typically offers the most agreeable circumstances. If you're seeking pleasant, dry and sunny weather somewhere else in the world, our weather planner can help you explore other options.
Castlebar Temperature in May
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Castlebar Weather by Month
Pick a month to see the average temperature, rainfall and sunshine in Castlebar - and find the best time to visit.
Daily Historical Temperatures
50-year average (1976-2025)
Based on our historical records, temperatures in Castlebar typically stay consistent throughout May, with daily highs averaging around 16°C (61°F). Nights are cold, with lows typically ranging from 6°C (43°F) to 9°C (48°F).
Average temperatures in May
Daily Historical Precipitation
50-year average (1976-2025)
Average daily rainfall for each day of the month based on long-term records.
Average precipitation in May
Historical weather records for Castlebar in May
Browse day-by-day weather records for Castlebar spanning 51 years. Select any month and year to see actual temperatures, rainfall, and conditions recorded on each day.
Castlebar historical weather extremes in May
Based on 50 years of weather observations (1976-2026), these are the most extreme conditions recorded in Castlebar.
- The hottest May day on record in Castlebar reached 25°C (77°F) (May 27, 2026).
- The coldest May day was on May 2, 1979, with a maximum of 5°C (41°F).
- Castlebar registered its coldest May night on May 14, 1977, with temperatures dropping to -1°C (30°F).
Best Places in Ireland in May
Find out more about the weather in Ireland and which places have the best travel conditions in this month. See all of Ireland in May →
Perfect weather is subjective. On this map perfect weather has been defined with temperatures between 20°C (68°F) and 29°C (84°F) and not too much precipitation (less than 90 mm (3.5 in) a month).
What to Wear in Castlebar in May
The weather can swing between comfortable and chilly in May, so flexibility is key. Pack a variety of tops, at least one warm layer, and both shorts and long pants. This gives you options no matter what the day brings. Expect heavy rainfall, so bring good rain protection and waterproof bags. Sunglasses could come in handy during the sunnier parts of your trip.
What To Do in Castlebar in May
We rated the following activities from 1 (least suitable) to 10 (best) to do.
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Swimming5/10 -
Cycling6/10 -
Walking6/10 -
Camping4/10 -
Outdoor sports9/10
Castlebar 3-Day Forecast
Temperature Rainfall Sunshine Humidity
See the full Castlebar climate overview or explore weather in Ireland.
Popular in May
Where to go in May - average daytime high across popular destinations.
Galway
16°C (61°F) Kilkenny
16°C (61°F) Westport16°C (61°F) Kenmare
16°C (61°F) Killarney16°C (61°F) Dublin16°C (61°F) Cork
15°C (59°F) Doolin15°C (59°F) 
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