Weather and water levels

Irish weather changes fast, and on the water you feel it more. A river stretch is pleasant in almost anything; a big lake in a strong wind is a different place. Check the forecast every morning, and again before a lake crossing.

Where the forecasts come from

• Met Éireann warnings for the Republic of Ireland, by county: met.ie/warnings. Yellow, orange and red warnings for wind, rain and thunderstorms all matter on the water.
• Met Éireann Inland Lakes Forecast for four lake areas: Lough Derg; Lough Ree; Lough Corrib and Lough Mask; Lough Key and Lough Allen. It gives wind force and direction, weather and visibility until nightfall, the wind overnight and an outlook (forecast). There is no lake forecast for the Erne, Lough Neagh or the canals.
• Met Office warnings for Northern Ireland, which cover the Erne, Lough Neagh and the Lower Bann: UK warnings. Met Éireann does not issue warnings for Northern Ireland.

The Today on the water page and each region page show the current warnings next to the forecast, with the time they were checked. When the warnings cannot be refreshed, we hold back the forecast too, so you never see one without the other.

Wind and the big lakes

The lakes on the inland waterways are big enough to build real waves. Lough Derg is about 40 km long and Lough Ree about 30 km, and the north-western part of Lower Lough Erne is wide, open water. Waves build fastest when the wind blows along the length of a lake, and they are short and steep: uncomfortable and tiring in a hire cruiser.

Our rules of thumb, the same ones behind the wind badge in the conditions panel:

• Force 4 (11 to 16 knots), or gusts above about 22 knots: choppy on open stretches. Think twice before crossing a big lake in a hire boat, and talk to your base.
• Force 5 (17 to 21 knots), or gusts above about 28 knots: consider staying in harbour or on a sheltered river stretch. Force 6 or more: stay in harbour.
• Look at the gusts, not just the average wind. A forecast of "force 4, gusting 6" is a force 6 day for docking.
• Plan crossings for the morning. On many summer days the wind picks up in the afternoon.
• Shelter matters. A harbour that is calm in a south-westerly can be uncomfortable in a north-easterly. Choose the night's stop with the forecast wind in mind.
• If you are caught out, slow down, take the waves slightly off the bow rather than side-on, keep everyone inside and wearing a lifejacket, and head for the nearest sheltered water (Erne Waterway Chart).

There is no official inland wind limit for these lakes. Hire companies set their own and may stop you crossing a lake in bad weather: their instruction wins over any plan, including ours.

Rain, fog, thunder and the sun

• Heavy rain raises rivers within a day or two and makes currents stronger near weirs and bridges.
• Fog and low cloud happen on calm mornings in spring and autumn. Wait for it to lift; the marks are hard to see.
• Thunderstorms: get off the open lake and moor up. Stay inside the cabin.
• The sun reflects off the water: sun cream and sunglasses, even on a cloudy day.
• Sunset is your deadline. Hire boats may not cruise after dark, and finding a mooring at dusk is stressful. Check the sunset time before you set off: in the Midlands it is around 22:00 in late June, about 20:00 in early April, 20:20 in early September and 17:00 by the end of October.

Water levels

Water levels on the Shannon and the Erne are regulated, but they still rise in wet weather and fall in dry spells. The Office of Public Works publishes live readings from gauges along the Shannon, Lough Ree, Lough Allen, the Erne in Co. Cavan, the Barrow and Lough Corrib (waterlevel.ie); our conditions widget shows the nearest one with its trend. The readings are provisional and our "low / normal / high" bands are our own, so do not use them to decide whether there is enough depth for your boat.

What a level means for you (Special Marine Notice 1/2026):

• High water can hide marks, reduce the air draft under bridges (Killaloe has about 3.85 m at normal summer level) and flood harbour walkways. Wear lifejackets on deck and step ashore with care.
• Low water makes the edges of the channel shallow. Keep to the middle, slow down, and avoid short cuts. On the canals it can also mean closed locks, as in the dry summer of 2026 (Marine Notice 88/2026).
• Between Ardnacrusha and Limerick the current can be dangerous: Waterways Ireland advises against travelling when more than one turbine is running.

Winter cruising

From November to mid-March lock hours are short, services at public moorings are off, and maintenance closures are common. Waterways Ireland asks boaters to check with its Inspectorate or operations staff before travelling between 1 November and 17 March (Shannon boater information). The days are short too: plan on a few hours of cruising, not a full day.