Snow star crystal 1.5mm diameter grown on an electric needle: Photo Ken Libbrecht. Snow covered Stevenson screen.

Llansadwrn (Anglesey) Weather:
Snowdonia Snowline Report

Logo: Llansadwrn Weather - Melin Llynnon, Ynys Môn.

Snowdonia Mountains Winter Season 2020/21

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Current snowline histogram. Snowline histogram

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Snow on summits of the Snowdon Horseshoe on 4 January 2010.


October 2020

Snow fell on Cairngorm on the 1st, but soon disappeared, there was a little broken snow on the 10th. Ice precipitation was seen on Y Garn and other Snowdonia summits on the 25th late in the afternoon.

November 2020

Snow fell on Penyfan in the Brecon Beacons on the 3rd, ice precipitation fell on the Snowdonia summits during the day and there was snow on Cairngorm on the 4th and 13th. The first snow of the season to settle and produce a covering fell on Yr Wyddfa, Snowdon, and highest summits of the Carneddau on the 19th November, later than usual.

December 2020

There was ice precipitation, snow likely at high altitude, overnight on 2/3rd. Snow had settled above 2000 ft in the afternoon when the cloud lifted. Snow on Snowdon.On the 4th there was snow above 2000 ft, moderately deep at higher altitudes. Snow persisted above 2250 ft until the 10th thereafter snow patches on C. Dafydd remained until rising temperature and heavy rain melted them. Fresh snow had fallen on the Carneddau and Snowdon. There was a sprinkling of snow on Carnedd Llewelyn on the afternoon of the 20th and some remnant icy patches seen above 3125 ft on the 22nd. On the 24th further light snow fell on the Carneddau and Snowdon and settled as low as 2250 ft on northern slopes and was still there on Christmas Day. By Boxing Day the 26th broken snow was lying at 2750 ft with icy remnants at 2500 ft. The snowline was at 2000 ft on the 27th and on the 28th fresh snow fell as low as 450 ft on the northern slopes of the Carneddau where light with moderate to heavy falls at increasing altitude with strong winds blizzard-like conditions on the summits. On the 29th and 30th snow was lying at 1500 ft, further snow on the 31st brought snow as low as 750 ft in places.

January 2021

Covid-19: Wales in under alert level 4 lockdown. This means you must not drive to Snowdonia from anywhere for recreational purposes, it is not regarded as an essential journey. You can take exercise walks in the hills locally, but you must start and finish at home and not take risks that would put extra pressure on emergency services. The car parks are closed and the police will turn you away. Vehicles have been towed away and fines issued.

On the 1st snow was lying at 1500 ft with 30% cover at 1250 ft, rising to 1800 ft with 30% cover at 1500 ft on the 3rd. Further snow at times up to the 5th generally above 1000 ft with some heavier falls, particularly at higher altitude. The Eryri Warden reported deep snow on the Llanberis path to Snowdon.Clouds and snow cover Carnedd Llewelyn. More snow fell on the 8th as low as 300 ft in places including SE Anglesey. On the 9th there was a sprinkling of snow on Penmaenmawr Mountain. On the 10th after further precipitation snow was lying at 450 ft on the northern slopes of the Carneddau. A large amount of snow had fallen in places at higher altitudes but, after a significant snowmelt in rain overnight the snowline on the 11th had risen to 2000 ft. Despite rain on several days some broken on the summits of the Carneddau and snow patches at 2000 ft survived until the 15th when snow cover was seen again above 2850 ft with 30% cover above 2500 ft. On the 17th there was a large snow patch on C. Dafydd at 2250 ft with ice precipitation during the day around the summits. On the 18th a sprinkling of fresh snow was seen in the morning above 2500 ft. Snow fell again and was seen as low as 1000 ft on the 21st especially in the west, lying at 1500 ft on the Carneddau.

Snow on the Carneddau Mountains outlines enhanced by windblow.

Windblown snow enhances topographic features on the Carneddau Mountains. On the 22nd snow was lying at 2000 ft, after further snow 1500 ft on the 23rd and 1000 ft on the 24th with some as low as 500 ft. By the 27th a thaw had set in with some broken snow remaining above 3000 ft and snow patches at 2000 ft. Snow patches persisted on the 29th before fresh snowfall on the 30th left lying snow at 1000 ft at Ogwen and sprinklings at 500 ft. On the 31st light snow was lying generally about 1500 ft with a good covering on Moel Eilio, somewhat resembling Mt. Fugi. Visibility was excellent, windblow of snow had resulted in outlines of peaks, ridges, cliffs, snow drifts and snow gullies being unusually clearly defined.


February 2021

Snow was lying at 1800 ft with 30% cover at 1500 ft on the 1st that became broken leaving on the 3rd lines of old drifted snow on north facing slopes as low as 500 ft. Snow patches and some old cornice snow was seen on the 4th and 5th at 3000 ft, with frequent snow patches at 2250 ft. Snow fell overnight 5/6th leaving a slight covering above 2500 ft. On the 7th snow was lying at 2250 ft and was lying thinly and broken on the 8th with remnants at 2000 ft and below in places. On the 10th some more snow had fallen moderate above 2500 ft on the Carneddau, with cornices on some cliffs, the snowline was at 2250 ft and 30% cover at 1800 ft. Most snow had thawed by the 15th.


March 2021

There was no snow on the mountains on the 1st of the month. Light hail and snow fell on the 11th and was lying at 2750 ft on the morning of the 12th remnants at 2850 ft survived until the 17th. Light snow fell on the 26th lying at 2500 ft and again on the 27th at 2000 ft.

April 2021

April snowfall on Carnedd Llewelyn.A light sprinkling of snow from showers on a cold front was seen at 1750 ft on the Carneddau, Snowdon and at 1000 ft near Ogwen at 0900 GMT on the 5th. Further showers on the tops at times with snow pellets in SE Anglesey at 1620 GMT. Light snow fell on the mountaintops on the 28/29th and on the 29th was lying at 2750 ft on the eastern ridge leading up to Carnedd Llewelyn.


May 2021

There was a little snow on the highest summits on the 1st of the month. fresh snow fell on the 4th and was lying at 2875 ft in the morning with some as low as 2500 ft eastward of Carnedd Llewelyn. On the 5th light snow was lying at 2000 ft with some as low as 1850 ft. More snow had fallen on the 6th with sprinklings as low as 1250 ft in places, but this soon thawed leaving the snowline at 2000 ft. On the 7th slight snow (60% cover) remained at 3150 ft with remnants in places at 2750 ft.


Snowdonia snowline current histogram.

  • You can view the snowline histograms for previous years here:

  • Winter 2019-2020. Winter 2019-2020
    Winter 2018-2019. Winter 2018-2019
    Winter 2017-2018. Winter 2017-2018
    Winter 2016-2017. Winter 2016-2017
    Winter 2015-2016.  Winter 2015-2016

  • You can view complete snowline reports for previous years here:

  • Winter 2019-2020. Winter 2019-2020
    Winter 2018-2019. Winter 2018-2019
    Winter 2017-2018. Winter 2017-2018
    Winter 2016-2017. Winter 2016-2017
    Winter 2015-2016. Winter 2015-2016

  • For earlier archived reports refer to the Site Map.



    Observations are made as near to 0900 GMT as possible. I have a good view from Llansadwrn, weather permitting, across the Menai Strait towards the Snowdonia Mountains. I can see the northern slopes of the mountain range from Moel Eilio (west of Snowdon), Snowdon summits (Yr Wyddfa and Crib Goch), the Glyderau and Carneddau to Foel-fras and Drum to the east of the range near the Conwy Valley. With the aid of binoculars I make daily records that include any ice precipitation observed, the lowest altitude of snow lying at ( >= 50% cover), at ( >= 30% cover) and snow patches. I aim to update the diagram during the season at least twice weekly if there is any snow.

    Designed and written by Donald Perkins, Copyright © 1998 - 2021. All Rights Reserved.

    Page first published 30 September 2020

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