Weather

Forecast#

Weather now and the coming 48 hours, with a choice of forecast source.

The row under the headline is the place: your device location by default. Tap Change to search for a town, drop a pin or type coordinates; Use GPS goes back to where you are. The place is shared with the rest of the app and remembered until you change it.

The line under it is the source. Automatic picks the national weather service where there is one and Yr (MET Norway) elsewhere. Tap it to choose another source; only sources that cover the place are offered. If a source you chose doesn't cover a new place, the screen says so and shows Automatic instead.

A few words on the next 24 hours: when rain (or snow) starts or stops, or that it stays dry. An hour counts as wet with 0.2 mm or more, with any amount under a rain, drizzle, snow, sleet or shower sky, or, when a source gives no amounts, with a rain chance of 60% or more. Only hours that have rain figures count: if they stop early, the headline says “until at least” instead of promising a dry day. Daily-only sources show today's wording.

The next 48 hours from left (now) to right, by the place's own clock. The curve is the temperature: higher is warmer, and its colour runs from cool blue at the bottom to warm amber at the top. The warmest and coldest values are written on the curve.

Bars under the line are rain in each hour: a full bar is 4 mm or more in an hour (heavy rain), and a brighter bar means a higher chance. Shaded columns are night (between sunset and sunrise, calculated on your phone), dashed lines are midnight with the new day's name, and the small figures under the ribbon are the hours. The sky is drawn every six hours along the top.

Above the ribbon: this hour's temperature and sky, what it feels like (wind chill or humidity included), the wind with its compass direction and the chance of rain.

Forecast summary#

The source’s written outlook or a summary written by AI.

A short written outlook. Where the service publishes its own (marked Outlook from …), you read the forecaster's words. Otherwise it is marked Summary written by AI: written on the iCaelum server from the same forecast when it was fetched. It is a reading aid; the table is the forecast itself.

The AI receives every available hour in the summary period, marked wet or dry using the same rule as the headline. If its wording still contradicts the first forecast hours, iCaelum hides that summary. Use the hourly table for the precise timing of short spells of rain.

Hourly forecast#

The hourly forecast with the measurements supplied by its source.

Every hour (or every 3 hours for some sources) with only the columns the source gives. Time stays fixed on the left while the other columns scroll sideways; Swipe for more shows while columns are hidden to the right. A dash means the source has no value for that hour.

Columns: the sky; the weather in words; rain chance; rain (amount in the hour); cloud cover; temperature and what it feels like; humidity; air pressure at sea level in hectopascals; wind speed with the direction it blows from; gusts; and the UV index. Tap the order line above the table to show humidity or wind straight after the temperature.

Colours are a second cue only; the number always carries the value.

Daily forecast#

The forecast for the days ahead.

The daily forecast summarises the days available from the selected source. Forecast length and the fields provided can differ between providers; choose a source rather than assuming every provider offers the same table.

Some services, such as the Hong Kong Observatory, publish days rather than hours. The hero then shows each day's low and high as a bar on one scale shared by all the days, so a warmer day sits further right; the days are listed in full below with the service's wording, rain and wind.

Rain radar#

Open the full rain map and choose a radar provider.

Weather radars send out pulses and listen for the echo from raindrops, snow and hail, so they show where it is raining right now and where the rain is heading. Each radar here is the provider's own website, opened inside iCaelum and centred where the site allows on the place chosen for the whole app: your location by default. The place button at the top of a radar changes it.

Wind#

Current speed, gusts, direction and the flowing wind map.

The wind now at the centre of the map: its speed, gusts and direction, drawn as flowing lines on the map. The map opens on the place chosen for the whole app (your location by default); the place line and the search button change it. Move or zoom the map to read the wind somewhere else.