Schiehallion

Mountain Prominent Scottish mountain once used to estimate Earth's mass

Conical mountain in Perthshire popular with hillwalkers; Schiehallion is known for well‑waymarked routes and the 18th‑century experiment that estimated Earth’s mass.

Main image

Schiehallion is a conical mountain in Perthshire, Scotland, reaching about 1,083 metres and known for its distinct shape and clear summit views.

Schiehallion became notable in the 18th century as the site of the Schiehallion experiment, an early geophysical measurement led by Nevil Maskelyne intended to estimate the Earth’s density; the mountain’s regular shape made it suitable for the survey. It has since remained a popular mountaineering and scientific landmark.

The mountain sits on the edge of the Highlands in central Scotland near Loch Rannoch and is accessible from nearby glens and small communities in Perthshire.

  • Height: The mountain rises to about 1,083 metres and is one of the more prominent peaks in Perthshire, favoured by hikers for straightforward but rewarding ascents.
  • Scientific history: An 18th-century scientific experiment to estimate the mass of the Earth - the Schiehallion experiment led by Nevil Maskelyne - was carried out on this mountain, giving it scientific as well as recreational significance.

What to See #

  • Summit: The broad summit ridge at 1,083 metres that provides a clear, conical profile and panoramic views across central Scotland.
  • Ascent routes: The main ascent paths from the glens to the east and west, used by hillwalkers to reach the summit and enjoy the mountain's well-defined trails.
Schiehallion
Schiehallion, Perth and Kinross, Scotland (grid reference NN 7197 5940)
56.6667, -4.1000
Free (access via public trails); mountain bothy or guided fees vary

How to Get to Schiehallion #

Access from the A827 (Braes of Aberfeldy) or via the village of Tummel Bridge. The standard route starts from the Strominish car park (near the A827); allow 2-4 hours return depending on pace. The area is remote-use detailed Ordnance Survey maps and local weather reports.

Tips for Visiting Schiehallion #

  • Plan for unpredictable weather and bring a map-mobile coverage is unreliable on parts of the route.
  • Start early; the ascent rewards morning light and reduces the chance of afternoon storms.
  • Use properly fitted boots and poles for the rocky summit plateau-legroom on the ascent is limited and footing quickly becomes rough.

Best Time to Visit Schiehallion #

Late spring to early autumn for safer conditions and better visibility.

Summer
Jun-Aug · 5-18°C (41-64°F)
Best for long daylight and gentler conditions; midges may appear in low, wet areas.
Spring
Apr-May · 0-12°C (32-54°F)
Snow patches can remain; clear days give excellent views with fewer walkers.
Autumn
Sep-Oct · 0-10°C (32-50°F)
Crisp air and rich colours; shorter daylight and more changeable weather.

Weather & Climate near Schiehallion #

Climate

Schiehallion's climate is classified as Subarctic - Subarctic climate with cool summers (peaking in July) and freezing winters (coldest in February). Temperatures range from -2°C to 14°C. Heavy rainfall (2168 mm/year), wettest in January.

Best Time to Visit
MayJulyJune
Temperature & Rainfall
Temperature Range
26°
Warmest Month
-12°
Coldest Month
Monthly Conditions

January

January is cold with highs of 2°C and lows of -2°C. The wettest month with heavy rain (282 mm), mostly overcast skies, and breezy conditions.

20 Poor

Comfort

Feels Like Cold
C
Temperature
-2°
97%
Humidity
Very Humid

Weather

282 mm
Rainfall
9.5 m/s
Wind
Breezy
0.0
UV Index
Low
7.4h daylight

February

February is the coldest month with highs of 2°C and lows of -2°C. Significant rainfall (183 mm), mostly overcast skies, and breezy conditions.

22 Poor

Comfort

Feels Like Freezing
C
Temperature
-2°
95%
Humidity
Very Humid

Weather

183 mm
Rainfall
9.2 m/s
Wind
Breezy
0.1
UV Index
Low
9.3h daylight

March

March is cold with highs of 3°C and lows of -2°C. Significant rainfall (197 mm), mostly overcast skies, and breezy conditions.

32 Poor

Comfort

Feels Like Cold
C
Temperature
-2°
93%
Humidity
Very Humid

Weather

197 mm
Rainfall
8.6 m/s
Wind
Breezy
0.3
UV Index
Low
11.7h daylight

April

April is cold with highs of 6°C and lows of 0°C. Significant rainfall (114 mm), mostly overcast skies, and breezy conditions.

38 Poor

Comfort

Feels Like Cold
C
Temperature
-1°
89%
Humidity
Very Humid

Weather

114 mm
Rainfall
7.4 m/s
Wind
Breezy
0.6
UV Index
Moderate
14.0h daylight

May

May is cold with highs of 10°C and lows of 2°C. Significant rainfall (116 mm), mostly overcast skies, and breezy conditions.

48 Poor

Comfort

Feels Like Cold
C
Temperature
10°
87%
Humidity
Very Humid

Weather

116 mm
Rainfall
6.6 m/s
Wind
Breezy
0.9
UV Index
Moderate
16.2h daylight

June

June is cold with highs of 12°C and lows of 5°C. Significant rainfall (111 mm), mostly overcast skies, and breezy conditions.

46 Poor

Comfort

Feels Like Cold
C
Temperature
12°
87%
Humidity
Very Humid

Weather

111 mm
Rainfall
6.5 m/s
Wind
Breezy
1.1
UV Index
High
17.3h daylight

July

July is cool with highs of 14°C and lows of 7°C. Significant rainfall (119 mm), mostly overcast skies, and breezy conditions.

48 Poor

Comfort

10°
Feels Like Cool
10°C
Temperature
14°
88%
Humidity
Very Humid

Weather

119 mm
Rainfall
6.2 m/s
Wind
Breezy
1.0
UV Index
High
16.8h daylight

August

August is cool with highs of 13°C and lows of 7°C. Significant rainfall (139 mm), mostly overcast skies, and breezy conditions.

46 Poor

Comfort

10°
Feels Like Cool
10°C
Temperature
13°
90%
Humidity
Very Humid

Weather

139 mm
Rainfall
6.2 m/s
Wind
Breezy
0.8
UV Index
Moderate
14.9h daylight

September

September is cold with highs of 11°C and lows of 5°C. Significant rainfall (193 mm), mostly overcast skies, and breezy conditions.

42 Poor

Comfort

Feels Like Cold
C
Temperature
11°
92%
Humidity
Very Humid

Weather

193 mm
Rainfall
7.2 m/s
Wind
Breezy
0.5
UV Index
Low
12.6h daylight

October

October is cold with highs of 7°C and lows of 2°C. Heavy rain (233 mm), mostly overcast skies, and breezy conditions.

32 Poor

Comfort

Feels Like Cold
C
Temperature
94%
Humidity
Very Humid

Weather

233 mm
Rainfall
8.2 m/s
Wind
Breezy
0.2
UV Index
Low
10.2h daylight

November

November is cold with highs of 4°C and lows of 0°C. Heavy rain (236 mm), mostly overcast skies, and breezy conditions.

30 Poor

Comfort

Feels Like Cold
C
Temperature
96%
Humidity
Very Humid

Weather

236 mm
Rainfall
8.9 m/s
Wind
Breezy
0.0
UV Index
Low
8.0h daylight

December

December is cold with highs of 3°C and lows of -2°C. Heavy rain (245 mm), mostly overcast skies, and breezy conditions.

22 Poor

Comfort

Feels Like Cold
C
Temperature
-2°
97%
Humidity
Very Humid

Weather

245 mm
Rainfall
8.4 m/s
Wind
Breezy
0.0
UV Index
Low
6.7h daylight

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