The winter hat was soon on for protection as I set off on the 3.7 mile (6km) hike along the Ogwen valley towards the crags of Gallt yr Ogof and the arresting presence of Tryfan, which were clear as a bell in contrast to the Carneddau opposite where grey sky and mist plagued the tops. The two Gwern Gof campsites were busy with a host of small tents and walkers milling around. The track emerges on the A5 opposite the Glan Dena path over the Afon Denau, presenting a nice view of Y Garn from the bridge.

Approaching the farm on the access track, the line of the footpath is at odds with my latest mapping: a waymark directs us right uphill and shortly leftwards to a ladder stile crossing the wall well above the buildings. From here the first section of ascent via yellow-topped poles to another ladder stile is an often very wet slog, but beyond that things improve greatly. An attractive path follows the Afon Lloer into its cwm, home to the shy Ffynnon Lloer which stubbornly remains out of sight until higher up and a detour would be required to visit its shore.

Turning westwards, the rocky east ridge of Pen yr Ole Wen looms ahead, a hugely enjoyable ascent involving an easy clamber up a short rocky gully. Nearing the summit, the mist was still close to this level and was intermittently coming and going, affording occasional clear views below the mantle. Ffynnon Lloer and the eastern cwm are well seen from the rim.

The mist blew in and obscured everything on the traverse of Carnedd Dafydd but soon began to disperse on the rocky arc of Ysgolion Duon, finally revealing Carnedd Llewelyn ahead and clear views below the grey mist to Yr Elen and the northern Carneddau. The stony plateau had a very light dusting of snow, already disappearing fast, and the air was clearing beautifully, leaving superb skies and pin sharp views.

The SE ridge of Carnedd Llewelyn is always a joy to walk: a short descent from the bouldery dome and an easy stroll on a grassy path lead to the bold rocky crag of Craig yr Ysfa. It is well worth taking time to explore the edge of the battlements overlooking the wild and remote Cwm Eigiau far below, a little trodden pocket of Snowdonia that ranks among our favourites. The steep rocky descent to Bwlch Eryl Farchog involves a slabby move that causes a little consternation for some very nervous folk, but for most it's an easy clamber.

The steep rocky path up Pen yr Helgi Du is another fine ascent and height is gained quickly, arriving abruptly on the extensive flat grassy top. Although a little early I called it a day here, partly because of the good pitching ground and partly to split the two days evenly. As the sun sank over Y Garn and Foel-goch, the mist mantle was returning intermittently to the highest tops and producing vivid sky displays, finally bringing a fiery orange tinge to the cloud patterns. As the temperature dropped I appreciated the first outing of the stove this season for a hot drink.

The splendid sky vista of the evening must have evaporated away quickly for the tent was later aglow in the silvery light of the full moon, and so it remained throughout the night. The wind disappeared and the temperature plummeted, and the delicate silnylon fabric of the flysheet, initially taut, wrinkled into furls stiffened with thick frost. Another cheer for the stove in the calm chilled morning air.

The ground was so hard and frozen that when I heaved out the pegs, some of the guylines remained stuck to the surface ice and the tent stayed upright and pitched out by itself - "Look - no pegs!". Frost-encrusted silnylon is unbelievably cold, enough to numb the hands literally in seconds, and after several onslaughts I got the tent into its bag. After hopping about for a while with my hands inside my down jacket I had enough feeling to operate the camera.

Despite all this the sun quickly warmed the calm air and I set off down to Bwlch y Tri Marchog, a glorious crisp walk in the early light with views to match, while Cwm Eigiau and the west ridge of Pen Llithrig y Wrach were deep in frostbound shadow. The summit is a magical spot, fantastic views all around with Creigiau Gleision across Llyn Cowlyd far below.

The long descent of the south ridge of Pen Llithrig follows a thin path that becomes vague lower down, but nearing the lake I cut down directly to the shore path where I met one solo backpacker and later a group of them trekking along the lake. The autumnal oranges and browns of the bracken and heather made a colourful display on the steep slopes, intensified by the low sunshine and contrasting with the deep blue of the water.

Only at the far end around the dam are the rather scruffy engineering works obtrusive: today some heavy machinery was on the move and a construction crew was working. There is a path across the head of the dam traversing the slopes of spoil behind the main wall, assisted by little footbridges, to a ladder stile where a notice warns of unpredictable water levels just beyond, much the same as 'flash-flood' warnings on some riverside paths, but all was bone dry today.

A change of character now: Creigiau Gleision is a wild beast of heather, rock and boggy bits, and I was anticipating a squelchfest after the recent rain. My recently revived Stratos Mids were no longer waterproof and I was hunting replacement footwear, but for today I had wisely put on my Goretex socks. The thin path through the heather is hard to trace near the dam but asserts itself a bit higher up and meanders around to reach the ridge fence.

The fence is an easy guide across several very boggy flat stretches and an ascent to a corner where the cairn on the North Top comes into view ahead. From this rocky little bastion studded with white quartz there is a sudden and breathtaking view over Llyn Cowlyd to Pen Llithrig with Tryfan and the Glyderau beyond. The path, vague at times in the boggy interludes, continues to the main rocky top.

The thin path leads over the recently promoted Nuttall top of Craiglwyn and around the western flanks of the craggy tops of Moel Ddefaid and Craig Wen, a series of steep drops and boggy crossings, finally arriving on grassy terrain once more at the deep bwlch before Crimpiau, a much more frequented top where I could see a group of figures standing on its crown. It is a grand local viewpoint: on show are the Creigiau Gleision range, the Ogwen valley mountains and an aerial view of Llyn Crafnant, while the colourful moraines below Craig Wen form a foreground to the high Carneddau.

There are various paths and impostors descending eastwards, but eventually I arrived at the main track junction at the bwlch where I turned southwards for Capel Curig. The broad track follows the Nant y Geuallt, resembling a small stream itself at first, and is a fine return route to the village. Repaired with stone paving in parts, it curves around a colourful boggy plain and crosses a footbridge, turning westwards through woodland to descend directly to the main road junction.