“Wind and weather” menu: measured wind, forecasts, radar and currents

User guide · updated 19.10.2026

The wind blowing now, the wind on its way, rain and thunderstorms, and what the water is doing.

What this menu is for

The Navleman menu, with the “Wind and weather” tile circled. — Menu, then the “Wind and weather” tile.

A submenu, Station readings — the wind measured at the lakeside —, then the map layers listed directly, with no submenu: forecast wind (arrows, animation), rain and its probability, thunderstorm risk, named winds, currents and water temperature, fog, the MeteoSwiss radar and, at the bottom of the list, the webcams.

Waves and shelter are in Lake info and Sports outing.

The storm warning lights ashore take precedence over anything the app shows.

How to use it

Open the menu

Tap Menu, bottom right, then the menu's tile. At the top: 📖 User guide for this menu (this page) and ↺ Reset maps, which switches everything off at once.

At the top, the Station readings submenu: the wind measured by the nearest station, every 10 minutes; strong-wind warning at 25 knots, storm warning at 33 knots. Below, the map layers listed directly, then the animation intensity, “Refresh sky” and the Info panel (including the storm cell alert).

The open menu, with its list of map layers and a checkbox in front of each. — The open menu: one row per map layer.

Turn on a map layer

Tick a map layer's box to lay it over the base map; untick it to remove it. The arrow at the right of the row opens its info note: what the layer shows, its colour key, its source and what it doesn't tell you. An OFFLINE label marks a layer built into the app, which works without signal.

Why checkboxes? So that only what's useful right now goes on the map: ten layers switched on together become unreadable.

Two map layers ticked in the list; the arrow at the right of a row opens its info note. — Tick the box; the arrow on the right opens the layer's info note.

Reading the map

“Wind — arrows”: each arrow shows where the wind is going, and its length and colour show its strength. Here, a sample west-south-westerly wind over the Grand-Lac.

The map of the Grand-Lac covered in green arrows pointing east-north-east, with the time slider at the bottom. — Wind arrows: direction, and strength by colour.

Tap a point: the pop-up

As soon as a forecast map is switched on, the time slider appears at the bottom of the screen. Drag the slider: wind, rain, thunderstorms, waves, currents and temperature are recalculated for the chosen time, up to 24 hours ahead. Now returns to the current time.

Why drag it to your return time? On Lake Geneva the wind often changes in the afternoon: look at the map for the time you head back, not the time you set off.

The radar has its own ◀ ▶ player: the last observed hour, then the coming hour, computed by extending the movement of the rain (the time of forecast images is shown in orange).

The time slider at the bottom of the screen, circled: a “now” slider handle and a “Now” button. — The time slider: drag it to see the hours ahead.

How the data is cross-checked

The Sky maps come from the MeteoSwiss ICON-CH1 model (one-kilometre grid), served by Open-Meteo for a grid of points around the lake and interpolated between them: wind, gusts, rain, rain probability, thunderstorm risk (convective energy and inhibition). Fog comes from Open-Meteo's default model. The radar is the MeteoSwiss composite (1 km, every 5 minutes); its one-hour forecast is an extrapolation computed by the app, not a MeteoSwiss forecast. Currents and water temperature come from the Eawag 3D model, in three-hour slots. Named winds (bise, joran, vaudaire…) are inferred from the direction, strength, lake sector and time of day, based on the SISL description, then confirmed by measured gusts when a station provides them.

The readings also include LéXPLORE, a research station on the lake off Pully, and three club wind beacons of the OpenWindMap network, at Versoix, near Saint-Prex and at Morges: the wind at water level. These four measurements trigger neither wind warnings nor named winds.

Station readings

Actual readings from the MeteoSwiss SwissMetNet network, every 10 minutes: the nearest station, or the one you choose. Strong-wind warning at 25 knots, storm warning at 33 knots, by lake sector. “Open full panel” shows all stations. The orange light ashore is what counts.

The map layers in this menu

Storm cell alert. While you're under way, the app compares radar images five minutes apart to spot a cell and measure its movement. It uses the MeteoSwiss hail probability — a direct marker of deep convection, calculated from 1 April to 30 September — and, failing that, cores of heavy rain. It sounds when a cell is less than 30 km away and will reach you in under three quarters of an hour, and only after “Let's go”.

The slider steps through the coming hours for wind, rain, probability, currents and fog. The radar is an observation, not a forecast: it has its own player (◀ ▶) and does not follow the slider.

The MeteoSwiss composite (RZC product from the five Swiss radars, 1 km, one image every 5 minutes) is not made of tiles: the app decodes the file and draws it itself, so it stays sharp at every zoom level and the latest image remains available offline. About 30 KB per image.

The named winds identify the prevailing regime sector by sector — bise, joran, vaudaire, séchard, rebat, morget, môlan, bornan, or “le vent” from the south-west — and follow the time slider: you can see at what time the bise gives way to the joran.

The thunderstorm risk combines the energy available for convection, the lid that stops it from starting and the rain forecast for the same hour. It is a forecast of potential, not the detection of a storm cell.

The wind animation uses the most battery: it pauses in the background or after two minutes without touching the map.

Sources: MeteoSwiss (ICON-CH1 and radar), Eawag (currents), Open-Meteo (visibility).

➶ Wind — arrows

The forecast wind hour by hour, as arrows, across the whole lake. The time slider follows the cursor.

< 5 kn5–1010–1515–2020–27≥ 27 kn

Tip. Drag the time slider to watch the wind shift and build.

Good to know. A model forecast, not a measurement: for the actual wind, the SwissMetNet readings are on the Weather screen.

Source: Open-Meteo, MeteoSwiss ICON-CH1 model

💨 Wind — animation

The same wind field, as drifting particles: you see at a glance where the wind speeds up and where it shifts.

< 5 kn5–1010–1515–2020–27≥ 27 kn

Tip. The clearest way to see where the wind speeds up; it also uses the most battery.

Good to know. Same forecast as the arrows; only the way it is shown changes.

Source: Open-Meteo, ICON-CH1 model

🌧 Forecast rain in mm (ICON-CH1)

Forecast rain in millimetres per hour.

< 0,5 mm/h0,5–22–5≥ 5 mm/h

Good to know. A forecast: the real shower may fall nearby and an hour earlier.

Source: Open-Meteo, ICON-CH1 model

☔ Chance of rain (ICON-CH1)

The chance of rain, as a percentage.

5–30 %30–60 %60–80 %≥ 80 %

Good to know. A probability is not an amount: a 70% chance may bring three drops.

Source: Open-Meteo, ICON-CH1 model

⛈ Thunderstorm risk (ICON-CH1)

Thunderstorm risk, derived from forecast convective energy and inhibition.

low riskmoderate riskhigh risk

Tip. An orange or red zone does not mean a storm will break, but that one could: keep an eye on the sky and the radar.

Good to know. An indication of favourable conditions, not a detection: a storm can break outside the zone, and a red zone can stay calm. The orange warning light on shore is what counts.

Source: Open-Meteo, ICON-CH1 model (CAPE and CIN)

🏷 Named winds of Lake Geneva

Lake Geneva's named winds — bise, joran, vaudaire, séchard — inferred from direction, strength, sector and time, then confirmed by measured gusts when a recent reading exists.

Tip. The wind's name for each sector of the lake, hour by hour: you see at what time the bise gives way to the joran.

Good to know. A name is an interpretation, not a measurement. Two regimes can compete for the lake.

Source: Open-Meteo for the field, SwissMetNet for confirmation

🌀 Surface currents (Eawag 3D model)

The surface current 1 m below the water, as arrows, in three-hour slots.

< 2 cm/s2–6 cm/s6–12 cm/s12–25 cm/s≥ 25 cm/s

Tip. Useful for a long leg or drift: 0,15 m/s across for an hour is more than 500 m.

Good to know. A model: it ignores the local current at a river mouth after a flood.

Source: Eawag 3D Delft3D-Flow model, via the Alplakes API

↳ animated (drifting particles)

The same current, as drifting particles.

< 2 cm/s2–6 cm/s6–12 cm/s12–25 cm/s≥ 25 cm/s

Good to know. Same field as the arrows.

Source: Eawag 3D model

🌡 Surface water temperature (Eawag 3D model)

Water temperature 1 m below the surface, across the whole lake, in three-hour slots. The time slider follows the cursor.

< 6 °C6–88–1010–1212–1414–1616–1818–2020–2222–24≥ 24 °C

Tip. For swimming, diving and fishing: the temperature at 1 m, in three-hour slots.

Good to know. A model, not a measurement: near a river mouth, an outfall or in a shallow bay, the actual water can differ by several degrees. For the depth profile, see Menu › Diving.

Source: Eawag 3D Delft3D-Flow model, via the Alplakes API

🌫 Fog — forecast visibility

Forecast visibility hour by hour, to anticipate haze closing in over the lake.

visibility 6–8 km4–6 km2–4 km< 2 km

Tip. Worth a look on autumn mornings, before setting off.

Good to know. Not all models provide visibility; when it is missing, the layer says so.

Source: Open-Meteo, default model

🇨🇭 MeteoSwiss weather radar — last hour and 1-hour forecast

The Swiss precipitation radar, 1 km composite, refreshed every five minutes. The ◀ ▶ player shows the last hour, then the coming hour: the rain extended in the direction it is moving (time shown in orange). With your position, the bar tells you whether the rain is heading your way.

< 0,4 mm/h0,4–11–2,52,5–66–1515–40≥ 40 mm/h

Tip. The ◀ ▶ player steps through the last hour, then the forecast hour (time shown in orange): you see where the rain is going. With GPS, the bar announces “rain expected here in ~15 min”.

Good to know. The forecast extends the movement of the rain: it cannot see a shower being born or a storm forming on the spot. Reliable for about half an hour, indicative up to an hour. It is not a MeteoSwiss forecast.

Source: MeteoSwiss (radar images); forecast: extrapolation computed by Navleman

📷 Lakeside webcams

Webcams overlooking the lake, placed on the map: one click opens the live image on the operator's site. The harbour and beach pop-ups also link to the nearest one, 1 km away or less.

Tip. One click opens the live image on the operator's site.

Good to know. A webcam can go down or change address without warning. The image belongs to its operator: the app keeps no copy, so it does not work without a connection.

Source: OpenStreetMap (ODbL) and operators' pages (Roundshot, Skaping, City of Geneva, Sauvetage d'Ouchy) · list checked on 22.09.2026

What this menu tells you, and what it doesn't

What it tells you. Wind measured every 10 minutes, forecasts from MeteoSwiss's ICON-CH1 model, the radar, and currents and temperature modelled by Eawag.

What it doesn't tell you. A forecast is not a measurement: gusts, storms and wind shifts can come earlier, later or elsewhere. The radar forecast extends the movement of the rain: it cannot see a shower forming on the spot.

Navleman is a navigation aid, not an official nautical document: the official chart, the storm warning lights and the authorities' instructions always take precedence.

Open the Lake Geneva map