Methodology

Observed vs estimated

The main card says Observed at station only when a station observation less than 90 minutes old is available. Otherwise it says Estimated current conditions, taken from the forecast step covering the current time.

Next 24 hours

We show forecast steps whose start times fall in the 24 real hours from the start of the current hour, in the location's timezone. When clocks go back, the repeated hour is shown twice with its timezone abbreviation. When clocks go forward, the skipped hour does not appear. Steps longer than one hour are labelled and not split into hours.

Daily values

NWS and ECCC daily highs and lows are the provider's own values. For MET Norway we calculate them from hourly and 6-hour steps in each local calendar day and label them “calc.”. Daily precipitation totals add up non-overlapping periods only. Daily precipitation chance is the highest chance among the day's periods (never an average). Days the forecast does not fully cover are marked “partial”.

Feels like

We use NWS wind chill (air ≤ 10°C/50°F and wind ≥ 5 km/h/3 mph) and NWS heat index (air ≥ 27°C/80°F and humidity ≥ 40%), or ECCC's own humidex/wind chill in Canada. Outside those conditions we show the air temperature and say so.

UV and visibility

MET Norway's UV index assumes clear skies and is labelled as an estimate. Visibility is shown only when a station measures it; it is never inferred from cloud or fog.

Companion moods and backgrounds

Decorative only, not a risk assessment. Priority: severe alert, then hazardous wind (sustained ≥ 40 km/h or gusts ≥ 60 km/h), then snow/sleet/freezing rain, then rain, then cloud, then sun; night styling applies when the sun is down.

Automatic theme

Light mode from 30 minutes before sunrise, dark mode from 30 minutes after sunset, in the displayed location's time. Polar day is light and polar night is dark. If the light windows overlap on a very short night, light wins.

Clothing suggestions

Fixed rules based on temperature (or wind chill), chance and amount of precipitation, wind and UV. An optional comfort setting moves the temperature thresholds by 2.5°C per step. No assumptions are made about age, gender, health or activity.

Units

Values keep their original unit and precision internally and are converted only for display. Default units follow your country, approximately detected; you can change them under Display.