Loch Lomond & The Trossachs Midges in May — Risk, Peak Times, Kit
Noticeable at dawn and dusk. Repellent recommended. The first proper midge country going north from Glasgow. Loch Lomondside, the Trossachs lochs and the Arrochar Alps all hold strong populations. The east shore at evening in July is a textbook case of why head nets exist.
Current risk
Loch Lomond & The Trossachs in May: Moderate. Noticeable at dawn and dusk. Repellent recommended.
When they bite
Peak biting windows are dawn 6–8am and dusk 5–7pm. First proper warmth across the region. Trossachs woodland and Loch Lomond east-shore bog ground reach midge emergence threshold by mid-month. Arrochar Alps and Crianlarich tops still cool enough for ridge-and-summit exemption.
What to wear
- Smidge repellent (75ml)
- Light-coloured long-sleeve baselayer — midges have a strong preference for dark clothing.
Tactical notes
May is the transition month in Loch Lomond and the Trossachs. The first three weeks typically remain clean across most of the region. The last week often delivers the first proper emergence in the Loch Lomond east-shore bog ground (Inversnaid, north of Rowardennan), the Trossachs woodland floor at Aberfoyle and Loch Ard, and the [Glen Falloch](/glens/glen-falloch) approach at the north end of Loch Lomond. The Arrochar and Crianlarich high ground stays effectively midge-free throughout the month.
This is the last reliably clean window for the long Loch Lomond east-shore section of the [West Highland Way](/long-distance/west-highland-way). Walkers timing the northbound start for mid-May get the long-daylight Highland evenings (sunset after 9pm by month-end) without paying the June lochside-camp midge tax. The Inversnaid bothy and the wild camping pitches between Rowardennan and Inverarnan are at their best in late May. The [Rob Roy Way](/long-distance/rob-roy-way) Trossachs sections, the [Three Lochs Way](/long-distance/three-lochs-way) Balloch–Inveruglas circuit, and the [John Muir Way](/long-distance/john-muir-way) Helensburgh end all work similarly well.
For hill days, the Arrochar Alps Munros are at their best of the year in May. [The Cobbler](/hillwalking/corbetts/the-cobbler), [Beinn Ime](/hillwalking/munros/beinn-ime), [Beinn Narnain](/hillwalking/munros/beinn-narnain), [Ben Vane](/hillwalking/munros/ben-vane), [Ben Vorlich](/hillwalking/munros/ben-vorlich-arrochar-trossachs) all give long daylight, dry firm rock, manageable insect tax. The Crianlarich Munro cluster — [Ben More](/hillwalking/munros/ben-more-arrochar-trossachs) and [Stob Binnein](/hillwalking/munros/stob-binnein), [Cruach Ardrain](/hillwalking/munros/cruach-ardrain), [Beinn Tulaichean](/hillwalking/munros/beinn-tulaichean), [Beinn Chabhair](/hillwalking/munros/beinn-chabhair) — works similarly. [Ben Lomond](/hillwalking/munros/ben-lomond) from Rowardennan is the most-walked late-May Munro in Scotland. Carry a 75ml Smidge for the late-month evenings on the loch shore; head net mostly stays in the pack.