OpenWeathermap forecast temperature incorrect

Hello, I wanted to make my blinds close when it becomes too hot using the sensor.openweathermap_forecast_temperature entity. I notice that it has about the same value as the current temperature. It is now 11:00 AM and the Developer Tool Template gives me

{{ states.sensor.openweathermap_forecast_temperature.state }}

returns 17.68

{{ states.sensor.openweathermap_temperature.state }}

returns 17.73

but when I try to find the max temperature in the coming 12 hours myself, it returns 24.8

{{ max(state_attr('weather.openweathermap','forecast')[1]['temperature'],
 state_attr('weather.openweathermap','forecast')[2]['temperature'],
 state_attr('weather.openweathermap','forecast')[3]['temperature'],
 state_attr('weather.openweathermap','forecast')[4]['temperature'],
 state_attr('weather.openweathermap','forecast')[5]['temperature'],
 state_attr('weather.openweathermap','forecast')[6]['temperature'],
 state_attr('weather.openweathermap','forecast')[7]['temperature'],
 state_attr('weather.openweathermap','forecast')[8]['temperature'],
 state_attr('weather.openweathermap','forecast')[9]['temperature'],
 state_attr('weather.openweathermap','forecast')[10]['temperature'],
 state_attr('weather.openweathermap','forecast')[11]['temperature'],
 state_attr('weather.openweathermap','forecast')[12]['temperature'],
 state_attr('weather.openweathermap','forecast')[13]['temperature'],
 state_attr('weather.openweathermap','forecast')[14]['temperature'])
}}

Do I really have to make my own sensor? am I doing something wrong? is there something wrong with OpenWeatherMaps?

Thank you

I have the same issue too… I would like to use the expected high temperature over the next 6/12/18 hrs to determine if I need to run my furnace in the morning or to let the house “coast” and let the sun heat the house…

The HA Openweathermap documentation implies that the forecast temperature should be the expected high temperature over the next 12 hours… But in my case, like yours it simply “tracks” the current outside temperature within a fraction of a degree, which is useless…

Is there any update on this? I have the same issue and same use case

I thought about this today, and i assume, that the “general” value that the sensor returns, must be a near-future forecast (maybe 1h?). I didnt get too deep into the api documentation but found this solution to make another sensor based on the max value for the current day:
How to get max temperature for today from forecast?
I will see how accurate that is for me. I’m concerned, that you simply get the maximum out of the 5 values in 3h-distance that the api grabs this way. If the peak is between two of those values, this sensor could be too low.
But maybe its just me not understanding the functionality by now and its all fine.