Help & FAQ

Lenticularis is a paragliding weather decision-support system for Switzerland. It collects data from multiple weather networks every 5–30 minutes, lets you build graphical rule sets for your launch sites, and shows a GREEN / ORANGE / RED traffic-light decision that updates automatically.

The key differentiator: you define your own rules using real station data — no one-size-fits-all logic imposed on you.

You can browse the map and station data without an account. To create and save rule sets for your own launch sites, you need a free Pilot account — register at /register.

1. Sign in and go to Rule Sets.
2. Click ＋ New rule set.
3. Enter a name (e.g. Beatenberg Südstart) and click the map to pin your site.
4. Optionally pick a preset site to pre-fill conditions for a nearby launch — you can edit every threshold afterwards.
5. Add conditions in the Rule Engine section — pick a station, choose a field (wind speed, direction, etc.), set an operator and threshold.
6. Save. The map will show a traffic-light badge for your site within the next evaluation cycle (usually < 5 minutes).

Each colour reflects the outcome of evaluating all conditions in your rule set against live station data:

• GREEN — all conditions pass. Conditions at this site look flyable according to your rules.
• ORANGE — at least one condition returned ORANGE. Caution; monitor closely.
• RED — at least one condition returned RED. Flying not recommended by your rules.

This usually means one of:

• The rule set has not been evaluated yet — evaluations run on a scheduler; wait a few minutes and refresh.
• One or more stations referenced in your conditions have not sent data recently. Check Stations to see the last-seen timestamp for each station.
• You have no conditions defined in the rule set.

The scheduler evaluates all active rule sets roughly every 5–10 minutes, in sync with the fastest collector (MeteoSwiss every 10 min, Holfuy every 5 min). The timestamp shown on the map popup and analysis page tells you exactly when the last evaluation ran.

A rule set is a named collection of weather conditions attached to one launch site, landing zone, or opportunity area. Each rule set evaluates to a single traffic-light colour based on live (and forecast) station data.

Rule sets are pilot-owned and private by default. You can publish them to the public gallery for others to clone and adapt.

Yes — this is a core feature. Each condition row has its own independent station picker. You can freely mix stations from different networks in the same rule set. For example:

• Condition 1: Beatenberg wind speed < 30 km/h
• Condition 2: Niesen wind direction in 250–310°
• Condition 3: Interlaken METAR wind gust < 40 km/h

Preset sites are admin-curated rule set templates for well-known launch sites. When creating a new rule set you can browse presets, pick one that matches your site, and all conditions (with sensible default thresholds) are pre-filled — you can then edit every value freely.

Presets are a shortcut; they do not lock you in to any specific configuration.

In the rule set editor, toggle Public (gallery). Your rule set then appears in the community gallery where other pilots can browse and clone it. Cloning creates an independent copy in the other pilot's account — changes made by either side do not affect the other.

Conditions inside the same group are AND-linked — all of them must pass for the group to be satisfied. You can add multiple groups; each group behaves as one logical block.

Groups themselves are combined according to the combination logic setting (worst wins / majority vote).

Example — "site is GREEN only when wind is calm AND from the south":

• Group 1: wind speed < 20 km/h AND wind direction in 160–200°

Each condition row has a result colour (GREEN / ORANGE / RED) that is used when the condition is triggered (i.e. when the threshold is crossed).

• Assign RED to hard limits that make flying dangerous (e.g. wind gust > 50 km/h).
• Assign ORANGE to advisory limits that warrant caution (e.g. wind gust > 35 km/h).
• Assign GREEN to positive confirmation conditions (e.g. wind direction in the flyable arc) — the condition is triggered only when the direction IS correct, contributing GREEN to the overall result.

Worst wins is the default and most conservative logic. The overall site colour equals the worst individual condition result:

• Any condition returns RED → site is RED.
• No RED but any ORANGE → site is ORANGE.
• All GREEN → site is GREEN.

Use this when all conditions must be met simultaneously for a safe flight.

Majority vote picks the colour that appears most often across all condition results. It is useful when you have a large set of advisory conditions and want an overall indicator rather than a strict all-or-nothing check.

A Launch site (▲ Launch) represents the takeoff point. It appears on the map as a circle with a traffic-light colour. You can link one or more landing zones to it — the map then shows a coloured ring around the launch marker based on the best available landing decision.

A Landing zone (⚑ Landing) is typically the valley landing field. It shows its own traffic-light badge and can be linked from any number of launch sites. Conditions on a landing zone might monitor low-level wind or obstacles.

An Opportunity (✦ Opportunity) is a special location or condition window — for example a thermal trigger, an XC window, or a favourable airspace corridor — that is not a specific takeoff or landing. It renders as a diamond marker on the map with a subtle glow when GREEN.

Unlike launch/landing semantics, an opportunity rule set is purely advisory: "conditions are right for this kind of flying."

The Pressure delta field shows a second station picker (Station B). At evaluation time, the system computes |pressure_A − pressure_B| (absolute difference in hPa) and applies your operator/threshold to that derived value.

This is the standard method for detecting cross-alpine Föhn: a north–south pressure gradient above ~4 hPa indicates föhn risk.

For the classic south Föhn corridor, use valley-level stations on opposite sides of the Alps to get a clean cross-alpine gradient:

• South: Locarno-Monti, Lugano, or Bellinzona (Ticino, MeteoSwiss)
• North: Interlaken, Bern, or Altdorf (Bernese Oberland / Uri, MeteoSwiss or METAR)

Avoid high-altitude stations (e.g. Jungfraujoch) for pressure delta — they introduce altitude effects that mask the gradient signal.

Föhn is a warm, dry downslope wind that occurs when air masses are forced over the Alps. In Switzerland, south Föhn flows from Italy through mountain valleys (Reuss, Rhine, Rhône) to the north. It is characterised by:

• Strong, gusty winds in alpine valleys — dangerous for paragliding
• Rapidly clearing skies and exceptional visibility north of the Alps
• A strong north–south pressure gradient across the Alps
• Characteristic lenticular (lens-shaped) clouds above the ridge — the source of the app's name

Virtual Föhn stations do not have physical sensors. Instead, the backend reads real station measurements for each corridor and checks them against configurable thresholds:

• Wind conditions: one or more stations in the valley must report gust ≥ threshold from the föhn direction sector.
• Pressure gradient: |P_south − P_north| ≥ threshold_hPa (typically 4 hPa), indicating the cross-alpine gradient that drives föhn.

A corridor is labelled Active only when ALL station conditions in that corridor are met simultaneously. If some but not all are met, it shows as Partial.

• Green — no föhn signal; all corridors below thresholds. Safe.
• Orange — partial föhn indicators or pressure gradient building. Monitor closely.
• Red — föhn confirmed in at least one corridor. Exercise caution in affected valleys.

The pressure chart at the top shows the raw OTL − INT gradient over time, with the threshold line marked.

The system runs two forecast collectors from Open-Meteo (ICON seamless):

• Short-range: 30-hour horizon, refreshed every 3 hours — best for today and tomorrow.
• Extended: 5-day (120-hour) horizon, refreshed once per day — useful for planning trips.

On the map you can use the day/hour slider to replay both past observations and the forecast window.

The Forecast Accuracy page lets you compare past model runs against what actually happened. For any station and date range, it overlays:

• A solid line for observed values
• One line per model-run day (colour-coded), showing what the model predicted at each lead time

This helps you understand how reliable the forecast is for a specific station — some high-Alpine or valley stations have worse model skill than open-terrain stations.

A calendar day is counted as flyable if at least one evaluation of your rule set returned GREEN on that day. Evaluations that fall outside the daylight window (sunrise−1h to sunset+1h) are marked with a moon icon and excluded from the daylight-filtered counts.

The hourly heatmap shows the percentage of evaluations that returned GREEN for each hour of the day (UTC), aggregated across the selected time period. Darker green = more often flyable at that hour historically.

Note: times are in UTC. Swiss local time is UTC+1 in winter and UTC+2 in summer.

The trigger leaderboard ranks each condition in your rule set by how often it voted non-GREEN (ORANGE or RED), and attributes each trigger to the station that provided the data. This tells you which station and which field is most often the bottleneck — useful for tuning thresholds.

Each station shows a last seen timestamp on the Stations page. If a station hasn't reported in the last 60–90 minutes it may be:

• Temporarily offline or under maintenance
• Experiencing network issues at the remote site
• Rate-limited (Wunderground / personal stations)

If a condition references a stale station, the rule set evaluation will show a warning and the result may be UNKNOWN for that condition.

An Organisation is a shared workspace for commercial operators or clubs — for example a tandem paragliding school. Each org gets:

• Its own subdomain (e.g. vkpi.lenti.cloud) with a public traffic-light dashboard.
• A set of org-owned rule sets managed by org admins.
• Org members (org pilots) who can log in to see condition details and history.

Personal pilot accounts and organisation accounts are independent — an org admin can also have a personal pilot workspace.

The org dashboard aggregates the latest evaluation results from all rule sets belonging to that organisation and picks the worst colour (worst wins). If any launch site is RED, the overall org status is RED.

Logged-in org members can see the per-rule-set breakdown and condition details below the main traffic light.