How to read the weather page in winter: forecast, snow, wind and air numbers

Photo: Qasim Mirzaie

Start with the right place and the right time

The weather page opens on Kabul. Choose another province from the buttons at the top or from the list, and each province page also lists its districts: tap a district to see its next days. Provinces are read every hour and districts every three hours, and the small line at the bottom of the page says when the data was last checked. If the weather is changing fast, look at that time first.

The data comes from Open-Meteo, a free weather service that uses several forecast models, such as ICON, GFS and ECMWF. It gives the weather for a point, not for every valley. A mountain pass or a village high above its district centre can be much colder, windier and snowier than the number shown.

Temperature and "feels like"

The big number is the air temperature now, with the day's high and low. The "feels like" figure is the apparent temperature. Open-Meteo describes it as the perceived temperature, combining wind chill, humidity and sunshine.

Wind chill is how cold people and animals feel outdoors, because wind carries heat away from bare skin. The US National Weather Service notes that it does not apply to objects: a car radiator or a pipe will not cool below the real air temperature. So when "feels like" is far below the temperature, cover your face, hands and ears, but do not expect the water in a tank to freeze faster because of it.

Rain and snow: the percentage and the amount

Two different numbers answer two different questions:

• The percentage is the chance of rain or snow. Open-Meteo defines it as the probability of more than 0.1 mm of precipitation in the hour. A high percentage says it will probably fall, not that it will fall hard. The page shows the chance only when it is 30% or more in the hourly strip, and 20% or more in the sixteen-day list.
• "Rain today" in millimetres and "Snow today" in centimetres are the amounts. Snow is measured as depth of fresh snow: Open-Meteo says that dividing snowfall in centimetres by 7 gives the water it holds in millimetres, so 7 cm of snow is about 1 mm of water.

Photo: Ali Azad

Whether snow closes a road depends on the pass and on how much falls, which this page cannot tell you. Before a journey, check the roads and passes page and read how to drive in snow and ice.

Wind, gusts, pressure and visibility

• Wind is the steady speed in kilometres per hour, with the direction as a letter such as N, NE or W.
• Gusts are the strongest bursts: Open-Meteo gives them as the maximum of the preceding hour at 10 metres above the ground. A gust figure far above the wind speed means a rough, uneven wind, so take more care outdoors and on exposed roads.
• Pressure is shown in hectopascals (hPa), reduced to sea level so that places at different heights can be compared. One reading tells you little; use the forecast instead.
• Visibility is the distance you can see. Open-Meteo says low cloud, humidity and fine particles reduce it. A small number in the morning, in fog or smoke, is a reason to drive slowly.

Photo: Mirwais Mohammadi

Humidity, dew point and the sun

Humidity is the share of water vapour the air holds compared with the most it could hold at that temperature. The dew point is the temperature to which the air must cool to reach 100% humidity. The US National Weather Service advises looking at the dew point rather than humidity to judge how dry or damp the air feels, because humidity changes with the temperature alone.

The UV index follows the World Health Organization's scale: 0 to 2 needs no protection, 3 to 7 means seek shade at midday and wear a hat and sunscreen, and 8 or more means avoid being outside at midday. The page also names the band (low, moderate, high, very high, extreme). Sunrise and sunset times are shown too, useful for planning a journey in the short winter days.

The air figure and the sixteen days

The coloured air number is the US Air Quality Index. In winter it is often high in Kabul, because families burn more fuel and cold air keeps the smoke near the ground. Read why Kabul's winter air is worse, see every province on the air quality page, and for carbon monoxide at home read staying warm safely.

The sixteen-day list is a guide, not a promise. The US weather agency NOAA says a five-day forecast is right about 90% of the time and a seven-day forecast about 80%, while a ten-day forecast or longer is right only about half the time, because the further ahead a model looks, the less reliable its estimates are. Use the next two or three days to decide, and the later days to see a trend, such as a cold spell.

Do not travel on a mountain road because the page shows a clear sky in the city. Check the road itself first, and carry warm clothes and water.