Air, UV and pollen

Exposure dial#

UV, air quality and pollen over the next 24 hours.

A 24-hour clock that starts now at the bottom and runs clockwise; the small figures are the hours on your clock and the short white pointer is now. Each ring is coloured hour by hour on one risk scale, so you can see when to go out: UV on the outer ring, the European air quality index on the middle ring and pollen on the inner ring. A faint ring means no data for that hour; on the UV ring it also means the Sun is down or too low to give any UV.

The figure in the middle is the comfort score for this hour, from temperature, air quality and UV only. Pollen and warnings are left out of it on purpose and shown on their own, so a good score never hides high pollen or a warning.

Official warnings#

Weather warnings for the chosen place’s country.

Official warnings from MeteoAlarm, which gathers the warnings of the national weather services of 30 European countries. They come right after the dial, before the details. The screen finds the country from the chosen place; the menu lets you look at any supported country (Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, United Kingdom). Outside Europe there is no coverage.

Warnings are sorted from most to least severe. While the check runs, the section says it is checking. If the check fails, it says the warnings couldn't be checked; that never means there are none. Outside the countries MeteoAlarm covers, it says the place is not covered.

Weather right now#

Current conditions and the available weather assessment.

The temperature, the sky in words, humidity, wind and the rain in the current hour, in your units from Settings.

Safety#

Heat, asthma and road-condition indices with their limitations.

Asthma risk is the worse of air quality and pollen: high when the European air quality index is poor or worse (above 60) or any pollen group is high, moderate when air quality is moderate (above 40) or a pollen group is moderate. Where there is no pollen data (outside Europe) it rests on air quality only, and the row says so. Heat risk uses NOAA's heat index (temperature with humidity, dry heat included): caution from 27 °C, extreme caution from 32 °C, danger from 39 °C, extreme from 52 °C (NOAA's 80, 90, 103 and 125 °F). Road safety turns to caution or unsafe with fog, snow, freezing rain, thunderstorms, more than 1 or 5 mm of rain in an hour, or wind above 15 or 20 m/s.

Air, UV and pollen#

The exposure measurements and what their levels mean.

The strength of the Sun's ultraviolet light, on the WHO scale: 0 to 2 low, 3 to 5 moderate (protect yourself around midday), 6 to 7 high, 8 to 10 very high, 11 and above extreme. It peaks around solar noon and is much lower in the morning and evening, even on a hot day; clouds lower it but don't remove it.

The European air quality index (European Environment Agency) combines fine particles, ozone, nitrogen dioxide and sulphur dioxide into one number: below 20 good, 20 to 40 fair, 40 to 60 moderate, 60 to 80 poor, 80 to 100 very poor, above 100 extremely poor. Lower is better.

Fine particles are given separately: PM2.5 (particles under 2.5 micrometres, which reach deep into the lungs) and PM10, in micrograms per cubic metre.

Pollen grains per cubic metre of air, from a European pollen model. Grass is shown on its own; tree is alder, birch and olive added together; weed is mugwort and ragweed added together. Each group has its own levels, from the US National Allergy Bureau, the most widely used international scale. Grass: below 5 low, 5 to 19 moderate, 20 to 199 high, 200 and above very high. Tree: below 15 low, 15 to 89 moderate, 90 to 1,499 high, 1,500 and above very high. Weed: below 10 low, 10 to 49 moderate, 50 to 499 high, 500 and above very high. The dial's pollen ring shows whichever group is worst on its own scale in each hour. Pollen alerts use the same totals.

Pollen this week shows each group's daily average (tree and weed add their species together) with the peak day dashed. Pollen data covers Europe only; elsewhere it shows as low or no data.

Pollen this week#

Available pollen forecasts for the coming days.

Exposure alert settings#

Exposure notifications, thresholds and recent alerts.

Alerts on/off under the headline opens the settings. With alerts on, iCaelum checks where your iPhone is in the background (about every 15 minutes when iOS allows) and notifies you when UV, air quality, temperature, humidity, wind, rain or a pollen group crosses the level you set. Each alert fires once until the value goes back below the level. Alerts are always about where you actually are, never the place chosen at the top: that only changes what this screen shows.

They need location access set to Always and notifications allowed. The comfort score, asthma, heat and road alerts use the same levels as the Safety section and fire when the chosen level or worse is reached.