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Slieve Donard

Mountain

A steep peak at the Mourne range's edge, Slieve Donard draws walkers for its marked trails, views over Newcastle and the Irish Sea, and access to rocky ridgelines popular with day-hikers and hill runners.

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In this guide

Slieve Donard essentials

Address: Mourne Mountains (Slieve Donard), near Newcastle, County Down, Northern Ireland
Admission: Free (hiking)

About Slieve Donard

Slieve Donard is the highest peak in the Mourne Mountains and in Northern Ireland, rising to about 850 metres above sea level near the county coast. It dominates the skyline above the seaside town of Newcastle and is a frequent target for hillwalkers.

Popular routes include the Glen River / Donard Glen approach from the Newcastle side and steeper ridges from neighbouring valleys; most round trips from the valley take a few hours and are waymarked. The summit offers panoramic coastal and inland views on clear days and is crossed by the Mourne Wall, a prominent stone enclosure that links several of the range’s peaks.

The mountain takes its name from Saint Donard (Domangart), and the massif has been used for grazing and limited upland management for centuries. The Mourne Wall that crosses the area was constructed in the early 20th century to protect water catchments and remains a notable landscape feature.

Slieve Donard sits above the town of Newcastle on County Down’s coastal fringe, within the Mourne Mountains and roughly an hour’s drive south of Belfast depending on traffic. The area is upland moor and granite ridgeline terrain with valley access from the coast.

  • Height and hike time: Summit altitude is about 850 metres, and typical footpaths take several hours round trip from the valley car parks near Newcastle.
  • Safety note: Weather can change rapidly at elevation; many walkers use marked paths and carry basic navigation and waterproof gear outside summer months.

What to See#

  • Summit: The mountain summit reaches approximately 850 metres above sea level and forms the highest point in County Down and the Mourne Mountains.
  • Donard Glen route: A network of walking routes ascends from the coastal town of Newcastle, with one of the most-used approaches following the Glen River / Donard Glen valley.
  • Mourne Wall: A dry-stone barrier known as the Mourne Wall crosses several peaks in the range and runs close to the summit, built in the early 20th century to enclose upland catchments.
Things to Do
When to Go

Best Time to Visit Slieve Donard

For the safest and most pleasant conditions on Slieve Donard, visit in late spring through summer (May-September) when weather and daylight are most favorable for hiking.

Late spring-summer (best for hiking)
May-September · ~8-16°C
Milder, more stable weather and longer daylight make ascents and ridge walks safer and more enjoyable.
Autumn (cooler, variable)
October-November · ~3-12°C
Crisp conditions and fewer visitors, but weather can change quickly-be prepared for rain and wind.
Winter (cold and exposed)
December-February · ~0-8°C
Frequent wet, windy and occasionally snowy conditions; reduced visibility and slippery ground increase risk on the mountain.

Weather & Climate near Slieve Donard

Climate

Slieve Donard's climate is classified as Oceanic - Oceanic climate with cool summers (peaking in July) and cold winters (coldest in January). Temperatures range from 0°C to 16°C. Heavy rainfall (2226 mm/year), wettest in January.

Air Quality: AQI 26 Good
Best Time to Visit
JulyAugustJune
Temperature & Rainfall
Temperature Range
21°
Warmest Month
0°
Coldest Month
Monthly Conditions
Month Comfort Temp Feels Rain Sky Humidity Wind UV Daylight
January Poor -1° - 4° -5° 250 mm overcast 87% 12.7 m/s 0.0 low 7.7h
February Poor 0° - 4° -5° 178 mm overcast 87% 12.0 m/s 0.1 low 9.5h
March Poor 0° - 6° -3° 204 mm overcast 87% 11.0 m/s 0.3 low 11.7h
April Poor 1° - 8° -1° 145 mm overcast 86% 9.1 m/s 0.7 moderate 13.9h
May Poor 4° - 12° 4° 127 mm overcast 85% 8.3 m/s 1.1 high 15.8h
June Poor 6° - 14° 10° 134 mm overcast 86% 7.7 m/s 1.3 high 16.9h
July Acceptable 9° - 16° 12° 134 mm overcast 87% 7.4 m/s 1.2 high 16.4h
August Acceptable 8° - 16° 12° 168 mm overcast 87% 7.6 m/s 0.9 moderate 14.7h
September Poor 6° - 13° 6° 190 mm overcast 87% 8.9 m/s 0.6 moderate 12.5h
October Poor 4° - 9° 1° 230 mm overcast 86% 10.7 m/s 0.2 low 10.3h
November Poor 1° - 6° -3° 226 mm overcast 86% 11.7 m/s 0.1 low 8.3h
December Poor 0° - 5° -5° 240 mm overcast 87% 11.9 m/s 0.0 low 7.1h
Getting There & Around

How to Get to Slieve Donard

Slieve Donard sits above the town of Newcastle in County Down and is commonly climbed from Donard Park at the town end. Drive or take a public coach from Belfast to Newcastle (the road distance is about 50-60 km south, roughly a one‑hour drive depending on route); from Newcastle town centre the Donard Park trailhead is a very short walk (a few minutes) to the base of the main uphill path. There is public parking in Newcastle and marked footpaths up the mountain.

Tips for Visiting Slieve Donard

  • Start the Donard Park trail in Newcastle early in the morning to beat weekend walkers and to take advantage of clearer visibility from the summit on calm days.
  • Use the well‑marked Donard Park path for the standard ascent-this is the most straightforward public route and has established parking and access; alternative routes (e.g., Brandy Pad) are longer and less crowded if you want solitude.
  • Allow for rapid weather changes on the Mournes and check local mountain‑weather forecasts before setting out; many visitors underestimate how quickly visibility and conditions can deteriorate.