@idefix37 I guess it's not a color rendering issue, Did Windy lose a lot of details in smoothing the source data(GFS 0.25°)

[[245,[136,136,136,255]],[246.4,[136,136,136,255]],[246.5,[176,176,176,255]],[247.9,[176,176,176,255]],[248,[204,204,204,255]],[249.4,[204,204,204,255]],[249.5,[228,228,228,255]],[250.9,[228,228,228,255]],[251,[119,51,119,255]],[253.3,[119,51,119,255]],[253.4,[170,51,170,255]],[255.7,[170,51,170,255]],[255.8,[204,51,204,255]],[258.1,[204,51,204,255]],[258.2,[255,51,255,255]],[260.5,[255,51,255,255]],[260.6,[255,153,255,255]],[262.9,[255,153,255,255]],[263,[21,0,204,255]],[264.9,[21,0,204,255]],[265,[51,102,255,255]],[266.9,[51,102,255,255]],[267,[51,153,255,255]],[268.9,[51,153,255,255]],[269,[51,204,255,255]],[270.9,[51,204,255,255]],[271,[51,255,255,255]],[272.9,[51,255,255,255]],[273,[0,119,0,255]],[275.3,[0,119,0,255]],[275.4,[0,153,0,255]],[277.7,[0,153,0,255]],[277.8,[0,187,0,255]],[280.1,[0,187,0,255]],[280.2,[0,221,0,255]],[282.5,[0,221,0,255]],[282.6,[0,255,0,255]],[284.9,[0,255,0,255]],[285,[255,255,51,255]],[286.65,[255,255,51,255]],[286.75,[255,238,51,255]],[288.4,[255,238,51,255]],[288.5,[255,221,51,255]],[290.15,[255,221,51,255]],[290.25,[255,204,51,255]],[291.9,[255,204,51,255]],[292,[255,187,51,255]],[293.65,[255,187,51,255]],[293.75,[255,170,0,255]],[295.4,[255,170,0,255]],[295.5,[255,153,0,255]],[297.15,[255,153,0,255]],[297.25,[255,119,0,255]],[298.9,[255,119,0,255]],[299,[255,0,0,255]],[300.9,[255,0,0,255]],[301,[238,0,0,255]],[302.9,[238,0,0,255]],[303,[204,0,0,255]],[304.9,[204,0,0,255]],[305,[187,0,0,255]],[306.9,[187,0,0,255]],[307,[170,0,0,255]],[308.9,[170,0,0,255]],[309,[153,0,0,255]],[310.9,[153,0,0,255]],[311,[136,0,0,255]],[313.4,[136,0,0,255]],[313.5,[114,0,0,255]],[315.9,[114,0,0,255]],[316,[91,0,0,255]],[318.4,[91,0,0,255]],[318.5,[66,0,0,255]],[320.9,[66,0,0,255]],[321,[29,0,0,255]]]

Windy (GFS 0.25°):

Meteoblue (GFS 0.5°):

WeatherOnline (GFS 0.25°):

@idefix37 I'm just guessing if Windy smoothed the source data to make it look better

The temperature data(GFS 0.5°) render result on meteoblue,which also has many small patches,and the boundary is quite
https://www.meteoblue.com/en/weather/maps/#coords=5.65/37.766/99.822&map=temperature~hourly~GFS05~2 m above gnd~none

@idefix37 thank you! the result is not yet which I wanted,I think the same data source (GFS 0.25°) should render the same results,but the Weatheronline image has many small patches,and the boundary is quite sharp.
WeatherOnline Result:

so,I guess Windy did some smoothing on the data, I don't know if it's appropriate.
such as this picture

@idefix37 I picked up steps with numerical values on color legend, and other steps were interpolated by numerical values
[[245,[136,136,136,255]],[246.5,[176,176,176,255]],[248,[204,204,204,255]],[249.5,[228,228,228,255]],[251,[119,51,119,255]],[253.4,[170,51,170,255]],[255.8,[204,51,204,255]],[258.2,[255,51,255,255]],[260.6,[255,153,255,255]],[263,[21,0,204,255]],[265,[51,102,255,255]],[267,[51,153,255,255]],[269,[51,204,255,255]],[271,[51,255,255,255]],[273,[0,119,0,255]],[275.4,[0,153,0,255]],[277.8,[0,187,0,255]],[280.2,[0,221,0,255]],[282.6,[0,255,0,255]],[285,[255,255,51,255]],[286.75,[255,238,51,255]],[288.5,[255,221,51,255]],[290.25,[255,204,51,255]],[292,[255,187,51,255]],[293.75,[255,170,0,255]],[295.5,[255,153,0,255]],[297.25,[255,119,0,255]],[299,[255,0,0,255]],[301,[238,0,0,255]],[303,[204,0,0,255]],[305,[187,0,0,255]],[307,[170,0,0,255]],[309,[153,0,0,255]],[311,[136,0,0,255]],[313.5,[114,0,0,255]],[316,[91,0,0,255]],[318.5,[66,0,0,255]],[321,[29,0,0,255]]]

@idefix37 There are 38 color classifications in the temperature legend of Weatheronline,I have modified the color according to legend on Windy, but there are still differences between the two images. So I guess Windy's data may have been processed.

@idefix37 still smooth,There are many small patches on Weatheronlie and connected areas on Windy

The rendering effect of Weatheronline（https://www.weatheronline.co.uk/cgi-bin/expertcharts?LANG=en&MENU=0000000000&CONT=asie&MODELL=gfs25&MODELLTYP=1&BASE=202410101200&VAR=tmp2&HH=12&ZOOM=1&ARCHIV=0&RES=0&WMO=&PERIOD=） has many details, while Windy rendering is very smooth. Has Windy's data been smoothed