Forecast Data
This page provides information about the content of each individual forecast data package.
Further information can be found in the following places:
- Specific package content can be found on this page. Please refer to the navigation on the right
- Package output parameters can be found on the overview page
- Information about Weather Variables can be found on the Weather Variables page
General Packages
Basic
The basic
package contains the most common weather variables. Despite the name, the basic
package uses state of the art forecast technologies like mLM and nowcasting with real time corrections from nearby weather station and satellite and radar observations. Data are constantly updated to improve forecast quality.
Example URL: http://my.meteoblue.com/packages/basic-1h_basic-day?lat=47.558&lon=7.573&apikey=DEMOKEY
The basic
package offers a 7 day forecast of precipitation, temperature, weather condition, wind speed & direction, humidity, sea level pressure, predictability and uv-index.
The 7 day weather forecast on the meteoblue website uses the basic package to display daily and 3-hourly data. Data on the website and in the API is identical.
Temperature
The temperature
field is based on the mLM temperature forecast and is equivalent to a measurement 2 meters above ground. For complex terrain in the Alps and central Europe, meteoblue calculates specialized 700 m resolution domains to capture the precise local temperature. Thus changing the elevation can significantly change also the shape of the temperature curve, e.g. on a mountain peak, the diurnal variations seen in the valley can disappear almost completely. Outside Central Europe simpler elevation corrections are applied to account for the elevation difference between model topography and real topography. The elevation of the local topography at a given place is automatically determined using an 80m resolution digital elevation model, but it can also be specified manually with the &asl=
URL parameter as described here.
If measurements from a nearby weather station are available, the temperature forecast is optimized for this station. Whether or not a station is used can be seen in the current package. Per default degree Celsius is used, but Fahrenheit can be selected with the temperature unit URL parameter.
The height of 2 meters above ground is most commonly used. Temperature forecasts for surface and in the soil are part of the agro package.
The 2 meter temperature might not represent the the perceived temperature. High humidity, strong winds and intense radiation increase or decrease the felt temperature. The felttemperature
, tries to combine these factors.
For daily aggregations the minimum, mean and maximum is used. For 3 hourly values the values represents the reading at that point on time. It is not an average over 3 hours.
Precipitation
The precipitation
field is the amount of all types of precipitation like rain, snow, ice, hail and convective showers. The field convective_precipitation
only includes showers. Both fields must not be summed up. Precipitation is expressed as mm
or inch
depending on the precipitation amount unit parameter.
To calculate the amount of snow fall, the snowfraction
field can be multiplied with the precipitation
field. This snow fall amount in mm
can be multiplied with 7 to get the equivalent snow depth. Example 1 mm precipitation is approximately equivalent to 7 mm snow fall. On some days there might be mixed conditions with rain and snow fall.
The precipitation in the basic package is calculated using multiple models with the meteoblue mLM technology. It is corrected using radar observations for the previous hours and the next 2 hours with a radar nowcasting. This correction applies to hourly data as well as daily aggregations.
For one and 3-hourly data, the precipitation value is the total amount of the preceding time-interval, similar to a rain gauge measurement. Example: For 3 hour data the precipitation at 12:00 is the sum of precipitation from 9:00 until 12:00. This is often misinterpreted by users. With 1-hourly precipitation this issue still exists, but is less noticeable.
To visualize the precipitation in the surroundings, the basic data package offers a rainspot
to display rain in a 7x7 grid. Additional information is available here.
A more general description for precipitation amounts and probability can be found here.
rainSPOT
The rainSPOT represents the precipitation distribution around the chosen location. It is a 7x7 array encoded from south to north, west to east: 0000000000000011990009990000990000099000000000000
0 = no rain, 1 = light rain (0.2 – 1.5 mm), 2 = medium (1.5 – 5 mm), 3 = heavy (>5 mm), 9 = shower (0.02 – 0.2 mm)
Please mind that the first digit in the API output represents the bottom left cell in the rainSPOT (see red 0 in the figure above).
Weather Condition Pictogram
To classify weather conditions "sunny", "partly cloudy" or "overcast with rain" the pictocode
field uses a numeric number. It is very important to note, that hourly pictograms and daily pictograms use different numeric codes. The basic package uses hourly pictogram codes from 1-35 and daily pictogram code from 1-17.
The field isdaylight
can be used to switch between daylight and night-time pictograms.
3-hourly Pictograms use the same numeric code as 1-hourly pictograms. 6-hourly pictograms use the same numeric code as daily pictograms. The 12:00 3h-hourly pictogram represents the weather conditions from 09:00 to 12:00. Additional information is available here.
Wind Speed and Direction
Wind speed forecasts are also based on mLM and should be equivalent to a measurement on 10 meters above ground. Winds closer to the ground are usually slower. To obtain wind speed at 2 meters, multiply the 10 m wind speed by a factor of 0.74, which gives a very good agreement on average. Per default kilometers per hour are used. A different unit can be selected with the wind speed unit URL parameter.
Wind speeds tend to fluctuate to a certain degree within one hour as well as within one grid-cell. The hourly wind speeds are an average over 1 hour and in one grid-cell. Wind gusts can therefore be significantly higher. The wind package provides wind speeds at 80 meters as well as wind gusts.
Wind forecasts may not capture the precise local wind conditions which are influenced by terrain, vegetation or buildings.
Wind direction is indicated in degrees (0° north, 90° east, 180° south, 270° west). It is the direction the wind is coming from. For daily aggregations the dominant wind direction is calculated which accounts for the wind speeds of each direction.
Additional information about wind is available here.
Predictability
A single weather forecasts model cannot be optimized for all weather conditions and areas. meteoblue operates a large number of weather models and collects data from multiple national weather services. Some models are more suitable for complex alpine terrain, while other models calculate fog conditions more precise. By combining multiple forecast models with statistics and machine learning algorithms, meteoblue calculates a learning multi-model forecasts (mLM). A byproduct of this approach is the ability to estimate the accuracy of the current forecast for each location.
If the majority of forecast models predicts the same weather conditions for a given location and achieve consensus, a high predictability
is indicated. The predictability
is given in percent, as well as a predictability_class
which is just a simpler representation for the percentage value.
Package Content
Variable | Units | Description | Intervals | Aggregations (6h, day) |
---|---|---|---|---|
Precipitation* | mm, inch | Water amount | 1h, 3h, 6h, day | Sum |
Precipitation probability | % | Likelihood of precipitation actually occurring | 1h, 3h, 6h, day | |
Precipitation hours | h | Hours with precipitation | day | |
Convective precipitation* | mm, inch | Water amount, caused by convection e.g. thunderstorms | 1h, 3h, 6h, day | Sum |
Snow fraction | 0, 1 | information whether precipitation falls as rain or snow: 0 = rain, 1 = snow | 1h, 3h, 6h, day | Aggregations: range from 0 till 1 (mean of hourly values) |
Temperature | °C, °F | 2m above ground | 5, 10, 15, 20, 30 mins, 1h, 3h, 6h, day | Min, max, mean |
Felt temperature | °C, °F | 2m above ground | 5, 10, 15, 20, 30 mins, 1h, 3h, 6h, day | Min, max |
Temperature instant | °C, °F | Temperature at 00:00 O'clock | day | |
Index to 1h values | Index | Corresponding hourly Index to daily values | day | start, end |
Pictocode | 1 - 35, 1 - 17 | 1h & 3h: 1 - 35 day/night pictos, 6h & day: 1 - 17 iday pictos | 1h, 3h, 6h, day | |
Wind speed | m/s, km/h, kn, mph, bf | 10m above ground | 5, 10, 15, 20, 30 mins,1h, 3h, 6h, day | Min, max, mean |
Wind direction | °, 2 char, 3 char | 10m above ground | 5, 10, 15, 20, 30 mins, 1h, 3h, 6h, day | Dominant |
Relative humidity | % | Air humidity | 5, 10, 15, 20, 30 mins, 1h, 3h, 6h, day | Min, max, mean |
RH > 90% | h | day | ||
Sea level pressure | hPa | Adjusted to mean sea level | 5, 10, 15, 20, 30 mins, 1h, 3h, 6h, day | Min, max, mean |
rainSPOT | 0, 1, 2, 3, 9 | 0 ≤ 0.02 mm, 1 = 0.2 - 1.5 mm, 2 = 1.5 - 5 mm, 3 ≥ 5 mm, 9 = 0.02 - 0.2 mm | 1h, 3h, 6h, day | |
Predictability | % | 24h | day | |
Predictability class | 0 - 5 | 1 = very low, 5 = very high | day | |
UV-index | 0 - 11+ | Ground level | day | |
Is-daylight | 0, 1 | 1 = day, 0 = night | 1h, 3h |
*Precipitation is the total amount: Do not compute the sum of precipitation and convective precipitation.
Current
The Current data package contains current weather information, including observations and measurements. It returns current temperature, windspeed and condition measurement. It is not based on a single measurement, but combined from multiple weather stations using downscaling and interpolation algorithms. Current satellite and radar telemetry is used to adapt the weather condition pictogram. In case no weather station is nearby, a weather forecast model will be used.
Example URL: http://my.meteoblue.com/packages/current?lat=47.558&lon=7.573&apikey=DEMOKEY
Package Content
Variable | Units | Description |
---|---|---|
Pictocode | 1 - 17 | 1 - 17, iday pictos (6h & day data) |
Pictocode detailed | 1 - 35 | 1 - 35, day/night pictos (1h & 3h data) |
Temperature | °C, °F | 2m above ground, Temperature for indicated time |
Wind speed | m/s, km/h, kn, mph, bf | 10m above ground, Wind speed for indicated time |
Is-daylight | 1 = day, 0 = night | |
Is-observation | 1 = obs available, 0 = no obs | |
Zenith angle | ° | Angle between zenith and centre of the sun's disc |
Metar ID | Identification Nr. of the Metar Station which provides the data |
Clouds
The Clouds data package contains detailed cloud layer and sunshine duration forecasts.
Example URL: http://my.meteoblue.com/packages/clouds-1h_clouds-day?lat=47.558&lon=7.573&apikey=DEMOKEY
Package Content
Variable | Units | Description | Intervals | Aggregations (6h, day) |
---|---|---|---|---|
Low clouds | % | Cover of the sky | 5, 10, 15, 20, 30 mins, 1h, 3h, 6h, day | Min, max, mean |
Mid clouds | % | Cover of the sky | 5, 10, 15, 20, 30 mins, 1h, 3h, 6h, day | Min, max, mean |
High clouds | % | Cover of the sky | 5, 10, 15, 20, 30 mins, 1h, 3h, 6h, day | Min, max, mean |
Total cloud cover | % | Cover of the sky | 5, 10, 15, 20, 30 mins, 1h, 3h, 6h, day | Min, max, mean |
Visibility | m | Distance | 5, 10, 15, 20, 30 mins, 1h, 3h, 6h, day | Min, max, mean |
Sunshine Time | min/h | Direct sunlight, depends also on day length | 5, 10, 15, 20, 30 mins, 1h, 3h, 6h, day | Min/interval |
Fog Probability | % | The likelihood of fog to occur in the defined time and area | 5, 10, 15, 20, 30 mins, 1h, 3h, 6h, day | Min, max, mean |
Index to 1h values | Index | Corresponding hourly Index to daily values | day | start, end |
Sun and Moon
The Sun and Moon data package contains information about rising and setting times of sun and moon. Rise and set times are indicated as string “hh:mm”. There are two special cases: If the moon does not rise and/or not set the field will have the value "---". If the moon is shining the entire day, then moonrise will be set to “00:00” and moonset will be “24:00”. The same applies if the sun does not rise and/or set, this time for the suns fields.
Example URL: http://my.meteoblue.com/packages/sunmoon?lat=47.558&lon=7.573&apikey=DEMOKEY
Package Content
Variable | Units | Description | Intervals |
---|---|---|---|
Sunrise and sunset time | hh:mm | day | |
Moon rise and moon set time | hh:mm | day | |
Moon phase angle | degree | day | |
Moon age | days | day | |
Moon phase name | name | New, waxing crescent, first quarter, waxing gibbous, full, waning gibbous, last quarter, waning crescent | day |
Moon phase transit time | hh:mm | day |
Moonlight
The moonlight package contains parameters for assessing night sky conditions, providing information about the brightness of the sky under clear and actual conditions, the impact of moonlight, and the zenith angle.
Example URL: https://my.meteoblue.com/packages/moonlight-1h?lat=45&lon=5&apikey=DEMOKEY
Package Content
Variable | Units | Description | Intervals |
---|---|---|---|
Moonlight clear sky | % | Percentage of light w.r.t. luminance of full moon at average distance not considering cloud-cover | 5, 10, 15, 20, 30 mins, 1h |
Moonlight actual | % | Percentage of light w.r.t. luminance of full moon at average distance considering cloud-cover | 5, 10, 15, 20, 30 mins, 1h |
Nightsky brightness clear sky | lx | Illuminance of the nightsky in lux not considering cloud-cover | 5, 10, 15, 20, 30 mins, 1h |
Nightsky brightness actual | lx | Illuminance of the nightsky in lux considering cloud-cover | 5, 10, 15, 20, 30 mins, 1h |
Zenith angle | ° | Solar zenith angle, important for twilight estimates | 5, 10, 15, 20, 30 mins, 1h |
Web Colors
The Web Colors package contains the meteoblue HTML colour codes for web-formatting. For plotting numbers on the indicated colours, use the font-colour specified in the package.
Note: This package is only available in combination with a data package.
Example URL: http://my.meteoblue.com/packages/basic-day_webcolors?lat=47.558&lon=7.573&apikey=DEMOKEY
Package Content
Variable | Units |
---|---|
Temperature | °C, °F |
Felt temperature | °C, °F |
Wind speed | m/s, km/h, kn, mph, bf |
UV-Index | 1 - 11+ |
Predictability | % |
Agronomical Packages
Agro
The Agro data package serves agricultural purposes and contains soil and vegetation related weather variables.
Example URL: http://my.meteoblue.com/packages/agro-1h_agro-day?lat=47.558&lon=7.573&apikey=DEMOKEY
Package Content
Variable | Units | Description | Intervals | Aggregations (6h, day) |
---|---|---|---|---|
Skin / Surface temperature | °C, °F | Soil surface or skin | 1h, 3h, 6h, day | Min, max, mean |
Wetbulb temperature | °C, °F | 1h, 3h, 6h, day | Min, max, mean | |
Total evapotranspiration* | mm | 1h, 3h, 6h, day | Sum | |
Potential evapotranspiration* | mm | Assuming unlimited water supply | 1h, 3h, 6h, day | Sum |
Reference evapotranspiration* (ET_0) | mm | 1h, 3h, 6h, day | sum | |
Leaf wetness index | 0, 1 | Dew on leaves | 1h, 3h, 6h, day | Mean |
Soil temperature (0 - 10cm) | °C, °F | 1h, 3h, 6h, day | Min, max, mean | |
Soil moisture (0 - 10cm) | vol. % | 1h, 3h, 6h, day | Min, max, mean | |
Dew point temperature | °C, °F | 2m above ground | 1h, 3h, 6h, day | Min, max, mean |
Mean sensible heat flux | W/m | Mean energy flux of the surface energy balance which is used to heat(+) or cool(-) the air | 1h, 3h, 6h, day | Mean |
Index to 1h values | Index | Corresponding hourly Index to daily values | day | start, end |
* For further information about the different evapotranspiration datasets, please consult the variable documentation.
Agromodel Leaf Wetness
The Agromodel Leaf Wetness data package contains all relevant information for monitoring and forecasting leaf wetness.
Example URL: http://my.meteoblue.com/packages/agromodelleafwetness-1h?lat=47.558&lon=7.573&apikey=DEMOKEY
Package Content
Variable | Units | Description | Intervals |
---|---|---|---|
Leaf wetness probability | % | Probability of leaf wetness (0% = low probability, 100% = high probability) | 1h |
Leaf wetness rain index | 0 - 1 | Index describing the contribution of rain to leaf wetness (0 = no contribution, 1 = maximal contribution) | 1h |
Leaf wetness dew index | 0 - 1 | Index describing the contribution of dew to leaf wetness (0 = no contribution, 1 = maximal contribution) | 1h |
Leaf wetness evaporation index | 0 - 1 | Index describing the contribution of evaporation to leaf wetness (0 = no contribution, 1 = maximal contribution) | 1h |
The indices have been designed to allow the professional user to calibrate each of the three elements influencing leaf wetness according to his local conditions, in order to compute a site specific leafwetness probability.