This notebook goes over how to use the OpenWeatherMap component to fetch weather information. First, you need to sign up for an OpenWeatherMap API key:
  1. Go to OpenWeatherMap and sign up for an API key here
  2. pip install pyowm
Then we will need to set some environment variables:
  1. Save your API KEY into OPENWEATHERMAP_API_KEY env variable

​
Use the wrapper

%pip install --upgrade --quiet pyowm

Note: you may need to restart the kernel to use updated packages.

import os

from langchain_community.utilities import OpenWeatherMapAPIWrapper

os.environ["OPENWEATHERMAP_API_KEY"] = ""

weather = OpenWeatherMapAPIWrapper()

weather_data = weather.run("London,GB")
print(weather_data)

In London,GB, the current weather is as follows:
Detailed status: overcast clouds
Wind speed: 4.12 m/s, direction: 10°
Humidity: 51%
Temperature: 
  - Current: 12.82°C
  - High: 13.98°C
  - Low: 12.01°C
  - Feels like: 11.49°C
Rain: {}
Heat index: None
Cloud cover: 100%

​
Use the tool

import os

from langgraph.prebuilt import create_react_agent

os.environ["OPENAI_API_KEY"] = ""
os.environ["OPENWEATHERMAP_API_KEY"] = ""

tools = [weather.run]
agent = create_react_agent("openai:gpt-4.1-mini", tools)

input_message = {
    "role": "user",
    "content": "What's the weather like in London?",
}

for step in agent.stream(
    {"messages": [input_message]},
    stream_mode="values",
):
    step["messages"][-1].pretty_print()

================================ Human Message =================================

What's the weather like in London?
================================== Ai Message ==================================
Tool Calls:
  run (call_6vPq9neyy7oOnht29ExidE2g)
 Call ID: call_6vPq9neyy7oOnht29ExidE2g
  Args:
    location: London
================================= Tool Message =================================
Name: run

In London, the current weather is as follows:
Detailed status: overcast clouds
Wind speed: 4.12 m/s, direction: 10°
Humidity: 51%
Temperature: 
  - Current: 12.82°C
  - High: 13.98°C
  - Low: 12.01°C
  - Feels like: 11.49°C
Rain: {}
Heat index: None
Cloud cover: 100%
================================== Ai Message ==================================

The weather in London is currently overcast with 100% cloud cover. The temperature is around 12.82°C, feeling like 11.49°C. The wind is blowing at 4.12 m/s from the direction of 10°. Humidity is at 51%. The high for the day is 13.98°C, and the low is 12.01°C.