Build a Weather CLI Tool in 20 Lines of Python (Using a Free API)

#python #beginners #tutorial #discuss

I wanted a weather check in my terminal. No browser, no app, just type weather Berlin and get the answer.

20 lines of Python later, I had it.

The Complete Script

import requests
import sys

def weather(city):
    url = f"https://api.open-meteo.com/v1/forecast"
    # First, geocode the city
    geo = requests.get(f"https://geocoding-api.open-meteo.com/v1/search?name={city}&count=1").json()

    if not geo.get('results'):
        print(f"City '{city}' not found")
        return

    lat = geo['results'][0]['latitude']
    lon = geo['results'][0]['longitude']
    name = geo['results'][0]['name']
    country = geo['results'][0].get('country', '')

    # Get weather
    w = requests.get(url, params={
        'latitude': lat, 'longitude': lon,
        'current_weather': True
    }).json()['current_weather']

    print(f"\n  {name}, {country}")
    print(f"  Temperature: {w['temperature']}C")
    print(f"  Wind: {w['windspeed']} km/h")
    print(f"  Direction: {w['winddirection']}")

if __name__ == '__main__':
    city = ' '.join(sys.argv[1:]) if len(sys.argv) > 1 else 'London'
    weather(city)

Usage:

python weather.py Berlin
python weather.py "New York"
python weather.py Tokyo

Output:

  Berlin, Germany
  Temperature: 12.3C
  Wind: 15.2 km/h
  Direction: 220

Why Open-Meteo?

No API key required
No signup
No rate limit (within reason)
Global coverage
Free for non-commercial use

Compare this to OpenWeatherMap which requires an API key, or Weather.com which requires a paid subscription for decent access.

Add It as a Shell Alias

# Add to .bashrc or .zshrc
alias weather='python3 /path/to/weather.py'

Now just type weather Berlin from anywhere.

Extend It: 7-Day Forecast

def forecast(city, days=7):
    geo = requests.get(f"https://geocoding-api.open-meteo.com/v1/search?name={city}&count=1").json()
    loc = geo['results'][0]

    w = requests.get('https://api.open-meteo.com/v1/forecast', params={
        'latitude': loc['latitude'],
        'longitude': loc['longitude'],
        'daily': 'temperature_2m_max,temperature_2m_min,precipitation_sum',
        'timezone': 'auto',
        'forecast_days': days
    }).json()

    print(f"\n  7-Day Forecast: {loc['name']}, {loc.get('country', '')}")
    print(f"  {'Date':12} {'High':>6} {'Low':>6} {'Rain':>8}")
    print(f"  {'-'*34}")

    for i in range(len(w['daily']['time'])):
        date = w['daily']['time'][i]
        high = w['daily']['temperature_2m_max'][i]
        low = w['daily']['temperature_2m_min'][i]
        rain = w['daily']['precipitation_sum'][i]
        print(f"  {date:12} {high:>5.1f}C {low:>5.1f}C {rain:>6.1f}mm")

What CLI tools have you built?

Small Python scripts that solve daily annoyances are my favorite kind of coding. What is yours? Share in the comments — I am collecting ideas for a "developer CLI toolkit" article.

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