Build a Wi-Fi Weather Station

Monitoring the weather is a classic maker project. But why stop at displaying it on a small LCD? In this tutorial, we'll build a Wi-Fi Weather Station using an ESP8266 (NodeMCU) that serves a web page you can access from any phone or computer on your network!

How it Works

The ESP8266 will connect to your home Wi-Fi and act as a web server. When you type its IP address into your browser, it will send back an HTML page containing the current temperature and humidity readings from a DHT sensor.

What You'll Need:

NodeMCU ESP8266 Board
DHT11 or DHT22 Sensor
Jumper Wires & Breadboard
Arduino IDE (with ESP8266 board support installed)

Wiring

DHT VCC -> NodeMCU 3.3V
DHT GND -> NodeMCU GND
DHT DATA -> NodeMCU D1 (GPIO 5)

The Code

We'll use the `ESP8266WebServer` library. Make sure you also install the `DHT sensor library` by Adafruit from the Library Manager.


#include <ESP8266WiFi.h>
#include <ESP8266WebServer.h>
#include <DHT.h>

// Replace with your Network Credentials
const char* ssid = "YOUR_WIFI_SSID";
const char* password = "YOUR_WIFI_PASSWORD";

#define DHTPIN 5     // Digital pin D1
#define DHTTYPE DHT11   // DHT 11

DHT dht(DHTPIN, DHTTYPE);
ESP8266WebServer server(80);

void handleRoot() {
  float h = dht.readHumidity();
  float t = dht.readTemperature(); // Celsius

  String html = "<!DOCTYPE html><html>";
  html += "<head><meta name=\"viewport\" content=\"width=device-width, initial-scale=1\">";
  html += "<style>body{font-family: sans-serif; text-align: center; margin-top: 50px;}";
  html += "h1{color: #444;} .sensor{font-size: 2rem; margin: 20px;}</style></head>";
  html += "<body><h1>ESP8266 Weather Station</h1>";
  
  if (isnan(h) || isnan(t)) {
    html += "<p>Failed to read from DHT sensor!</p>";
  } else {
    html += "<div class=\"sensor\"><b>Temp:</b> " + String(t) + " °C</div>";
    html += "<div class=\"sensor\"><b>Humidity:</b> " + String(h) + " %</div>";
  }
  
  html += "</body></html>";
  
  server.send(200, "text/html", html);
}

void setup() {
  Serial.begin(115200);
  dht.begin();
  
  // Connect to Wi-Fi
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  
  Serial.println("");
  Serial.print("Connected! IP Address: ");
  Serial.println(WiFi.localIP());

  server.on("/", handleRoot);
  server.begin();
}

void loop() {
  server.handleClient();
}

Running the Project

Upload the code to your ESP8266.
Open the Serial Monitor (115200 baud).
Wait for the connection message. Copy the IP Address shown (e.g., 192.168.1.15).
Enter that IP address into your phone or computer's web browser.
Voila! You should see the live temperature and humidity.

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