Weather icons & lunar phase
The weather icon on each daily card and segment header, the moon phase badge in the corner, the wind arrow on the hero card — small details, all data-driven. Here's what they mean.
May 2026: Weather chips on segment cards and daily-log cards now use monochrome stroke SVGs instead of Unicode emoji. The previous emoji renderer had a known issue where the "fog" glyph rendered as a blank square on some macOS / Chrome versions. SVGs render identically across every browser and pick up the theme's accent colour.
Weather codes
The daily-stats card shows the dominant condition for the day at the trip's midpoint position, mapped to an emoji using the WMO weather code table:
| Code | Condition | Icon |
|---|---|---|
| 0 | Clear sky | ☀️ |
| 1 | Mainly clear | 🌤️ |
| 2 | Partly cloudy | ⛅ |
| 3 | Overcast | ☁️ |
| 45 | Fog | 🌫️ |
| 48 | Rime fog | 🌫️ |
| 51–55 | Drizzle | 🌦️ |
| 61–65 | Rain | 🌧️ |
| 71–75 | Snow | 🌨️ |
| 80–82 | Rain showers | 🌦️ |
| 85–86 | Snow showers | 🌨️ |
| 95 | Thunderstorm | ⛈️ |
| 96–99 | Thunderstorm with hail | ⛈️ |
Hovering the icon shows the WMO description text and the temperature at the time the daily summary was computed.
Lunar phase
A small moon emoji 🌑 🌒 🌓 🌔 🌕 🌖 🌗 🌘 in the corner of the hero card shows the moon's phase at the trip's start day. Useful context for night photography, sea kayaking, or the kind of walk where the brightness of the night matters.
The phase is computed locally — no extra API calls. The math uses Conway's algorithm: count days since the reference new moon (2000-01-06), divide by the synodic period (29.530589 days), take the fractional part, and pick the matching phase. Accurate to within ~6 hours for any date 2000–2100.
Wind arrow
The wind chip on the hero card during an active trip shows:
- A direction arrow ↗️↘️ etc. (8 cardinal directions, rounded from the live wind heading at the current GPS position).
- Wind speed in km/h.
Updates every minute via the wind layer data. If wind data is unavailable for the current position (very polar latitudes, mid-ocean dead zones), the chip just shows a calm indicator.
Day vs night colour
The hero card's accent shifts subtly between day and night based on the trip's local time, not the viewer's. So if you're in Australia and the user viewing the page is in Europe, the page still reflects Tereza's local 2 AM rather than the viewer's 5 PM.
Related
- Wind layer — full wind overlay.
- Temperature layer — temperature overlay.
- Analytics glossary — how daily stats are computed.
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