Which is the exact period for the hourly weather records?
WIth the hourly timeline we get hour points 0-23.
The period length is expected to be 1 hour. But how should we treat the 'datetime', as a start, end or a center point of 1-hour periods?
E.g. Considering the record with datetime = 01:00
Which one is correct?
Thank you for your question. The date time is either the instantaneous time or the end of the period depending on the element in question.
For instantaneous weather elements such as temperature, pressure and wind speed, the values are the values at the indicated time.
For aggregated values such as precipitation and snow fall, the values are the sum of the values for the past hour ending at the time indicated. For example 5mm of precipitation at 01:00 indicates 5mm fell between 00:00 and 01:00.
For more information, please see https://www.visualcrossing.com/resources/documentation/weather-data/how-are-weather-metrics-calculated-over-various-time-periods-in-different-weather-queries/
Regards
Visual Crossing Support
Hi,
From an API reply, it seems like the first option . 1AM = data from 1-2AM ?
I can give a data.json for 10/29 ran at 3:45AM (local time as location ) . The datetime for 3:00 shows data source as "fcst" .
Can you please confirm?
Sample query with removed API key is: https://weather.visualcrossing.com/VisualCrossingWebServices/rest/services/timeline/Taguig/2022-10-27/2022-10-30?unitGroup=metric
"
{
"datetime":"03:00:00",
"datetimeEpoch":1666983600,
"temp":26.7,
"feelslike":26.7,
"humidity":76.84,
"dew":22.3,
"precip":0.1,
"precipprob":100.0,
"snow":0.0,
"snowdepth":0.0,
"preciptype":[
"rain"
],
"windgust":46.1,
"windspeed":25.2,
"winddir":351.2,
"pressure":1000.0,
"visibility":24.1,
"cloudcover":100.0,
"solarradiation":0.0,
"solarenergy":null,
"uvindex":0.0,
"severerisk":10.0,
"conditions":"Rain, Overcast",
"icon":"rain",
"stations":null,
"source":"fcst"
},
"
Thank you for your question. The data 1am will generally be instantaneous values at 1am. The exception will be accumulating elements such as a rainfall or snow fall - they will be measured for the hour ending at the time specified (for example fain will be the sum of rain between 12 and 1am).
For recent hours, the API will return the latest forecast data for an historical hour if no weather station has reported for that hour. In most cases there will be stations near a requested location that will report but in some cases such as this location in the Philippines the data may not be available for a small number of hours.
Regards
Visual Crossing Support
Thanks a lot !
For days based data, what is the correct implementation? For a daily data marked with datetime of "10/28/2022" , will the data be for 10/28/2022 00:01AM - 11:59 PM ( All relative to local time zone of location probed ) or will this be for 10/29/2022 00:01AM - 11:59PM ?
As in the question is simply , "for data marked with datetimeX , is the data for dateX or dateX-1 or dateX+1" ?
The weather for the daily data will aggregate the hourly data for that particular day - for example the weather for 10/28/2022 will aggregate the hours from 10/28/2022 12:00AM to 10/28/2022 11:00PM.
Regards
Visual Crossing Support