Approximate Atmospheric Attenuation 1-350 GHz
(ITU-R P.676-10 (09/2013), Appendix 2)

Joachim Köppen Kiel June 2023

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The values are given with 4 decimal places, but please keep in mind that this is not the accuracy!
Unfortunately, the ITU documents do not contain an explicit statement on the accuracy of the resulting zenith attenuations. It seems plausible to assume that it is of the order of 1%.

The plot shows the dependence of the zenith attenuation on air temperature (at -10 (black), 0 (gray), 10 (blue), 20 (magenta), and 30 °C (red)) and relative humidity. The light blue area indicates 'normal' conditions in temperate zones.

Frequency [GHz]
Air pressure [hPa]
Temperature [C]
rel.Humidity [%]

Spec.attenuation [dB/km]
Zenith attenuation [dB]

Clouds at zenith [dB]
Elevation [deg]
Attenuation [dB]

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