## Dewpoint calculation script in Python

Using the well-known approximation to calculate the dew point temperature from the actual temperature and the relative humidity, it is very easy to write a small script that can do this calculation for us.

I choosed Python to do this job. Feel free to use this script for your own purposes:

```  import sys import numpy as np   # approximation valid for # 0 degC < T < 60 degC # 1% < RH < 100% # 0 degC < Td < 50 degC   # constants a = 17.271 b = 237.7 # degC   # sys.argv is program name T=float(sys.argv) RH=float(sys.argv)     def dewpoint_approximation(T,RH):   Td = (b * gamma(T,RH)) / (a - gamma(T,RH))   return Td     def gamma(T,RH):   g = (a * T / (b + T)) + np.log(RH/100.0)   return g     Td = dewpoint_approximation(T,RH) print 'T, RH',T,RH print 'Td=',Td```

The script expects two input parameters. First the temperature (in °C) and second the relative humidity (in %).

1. Simon, May 18, 2014:

Just wanted to thank you for your script. I implemented it to my home automation system to calculate when to ventilate my basement to reduce humidity.

2. huda, March 4, 2020:

I want to know how you obtain the constant value of a and b? or what is your reference? Thank you

3. hans, March 12, 2020:

Thanks so much for sharing!