Build An Esp32 Weather Station Using Wi-fi To, a ESP32 project

This project builds a Wi-Fi-connected weather station on an ESP32 that displays real-time conditions on a round 1.28-inch TFT display. The station fetches weather data from Open-Meteo API and shows temperature, wind speed, precipitation probability, and weather conditions with color-coded status indicators.

The guide provides a complete wiring diagram connecting the GC9A01A display to the ESP32 via SPI, a full parts list, ready-to-use firmware with Wi-Fi and API integration, and step-by-step assembly instructions. Builders will have a functional weather display that updates every 10 minutes and can be customized for any location by changing the latitude and longitude in the code.

Wiring diagram

Gather all the parts

Qty	Component
1	ESP32 development board ESP32-WROOM-32, Freenove ESP32, or equivalent ESP32 DevKit-style microcontroller board with USB programming support.
8	Male-to-female jumper wires A small set of Dupont jumper wires for connecting the ESP32 headers to the display connector or breakout lead set.
1	USB data cable for ESP32 USB cable for powering and flashing the ESP32. Use a real data cable, not a charge-only cable.
1	GC9A01 Round TFT LCD 1.28 inch 240x240 240x240 1.28 inch round IPS TFT LCD display module with GC9A01/GC9A01A driver IC. 240x240 RGB resolution, 4-wire SPI interface, and 3.3V/5V module input. Module-side labels are VCC, GND, DIN, CLK, CS, DC, RST, and BL/BLK. The display is write-only over SPI, so no MISO line is required for the LCD. Supported by Adafruit GC9A01A and TFT_eSPI libraries in Arduino-compatible firmware projects.

Assemble it in 5 steps

1. Keep the board unpowered

Unplug the ESP32-C3 SuperMini from USB before making connections. Place the GC9A01A display and board on a non-conductive surface.

The display is a 3.3 V logic device.
Do not connect the display to 5 V or VBUS.

2. Connect display power

Connect GC9A01A VCC to the SuperMini 3V3 pin. Connect GC9A01A GND to any GND pin on the SuperMini.

Power and ground should be connected before the signal wires.
Both devices must share GND.

3. Connect the SPI signals

Wire GC9A01A SCK (sometimes labelled CLK or SCL) to GPIO6. Wire MOSI (sometimes labelled DIN or SDA) to GPIO7. Wire CS to GPIO10.

Keep these three wires short to reduce display glitches.
This display is write-only; do not add a MISO connection.

4. Connect display control and backlight

Wire DC to GPIO3, RST to GPIO2, and BL or BLK to GPIO1. The firmware drives BL high to turn on the backlight.

Some GC9A01A boards label MOSI as DIN and SCK as CLK.
Check each module label rather than wire position; inexpensive modules may order header pins differently.

5. Review the complete wiring

Confirm: VCC→3V3, GND→GND, SCK/CLK→GPIO6, MOSI/DIN→GPIO7, CS→GPIO10, DC→GPIO3, RST→GPIO2, BL/BLK→GPIO1. Then connect the USB data cable to power and program the board.

The project is USB-powered; no external supply is required.
Recheck that VCC is on 3V3, not 5V, before connecting USB.

Review all connections

1. Connections between "gc9a01a_0" and "ESP32"

Function	gc9a01a_0	ESP32
`power`	VCC	3V3
`ground`	GND	GND
`spi`	SCK	GPIO 6
`spi`	MOSI	GPIO 7
`spi`	CS	GPIO 10
`digital`	DC	GPIO 3
`digital`	RST	GPIO 2
`digital`	BL	GPIO 1

Deploy the firmware

src/main.cppOpen in Schematik

// Amsterdam Wi-Fi Weather Station — ESP32-C3 SuperMini + GC9A01A 240x240 TFT
#include <Arduino.h>
#include <WiFi.h>
#include <HTTPClient.h>
#include <ArduinoJson.h>
#include <Adafruit_GFX.h>
#include <Adafruit_GC9A01A.h>

#define TFT_SCK  6
#define TFT_MOSI 7
#define TFT_CS   10
#define TFT_DC   3
#define TFT_RST  2
#define TFT_BL   1


// Hoisted type definitions
struct Weather { float temp, wind; int code, rain; bool valid; } weather;


// Forward declarations
String condition(int c);
String advice();
void centered(String s, int y, uint8_t size, uint16_t color);
void statusScreen(const char* title, const char* detail, uint16_t color);
void drawWeather();
bool fetchWeather();
void connectWiFi();

const char* ssid = "Sharvil";
const char* password = "";
const char* weatherURL =
  "https://api.open-meteo.com/v1/forecast?latitude=52.3676&longitude=4.9041"
  "&current_weather=true&hourly=precipitation_probability"
  "&timezone=Europe%2FAmsterdam&forecast_days=1";

Adafruit_GC9A01A tft(TFT_CS, TFT_DC, TFT_MOSI, TFT_SCK, TFT_RST);
const uint16_t BLACK=0x0000, WHITE=0xFFFF, GRAY=0x8410, DARK=0x2104;
const uint16_t AMBER=0xFBA0, CYAN=0x07FF, GREEN=0x07E0, RED=0xF800;


unsigned long lastUpdate = 0;
const unsigned long UPDATE_MS = 600000UL;

String condition(int c) {
  if (c == 0) return "CLEAR";
  if (c <= 3) return "PARTLY CLOUDY";
  if (c <= 49) return "FOG";
  if (c <= 59) return "DRIZZLE";
  if (c <= 69) return "RAIN";
  if (c <= 79) return "SNOW";
  if (c <= 82) return "SHOWERS";
  return "STORM";
}

String advice() {
  if (weather.code >= 51 || weather.rain > 40) return "TAKE AN UMBRELLA";
  if (weather.temp < 5) return "COAT AND SCARF";
  if (weather.temp < 14 || weather.wind > 35) return "WEAR A JACKET";
  if (weather.temp > 22 && weather.code <= 3) return "T-SHIRT + SUNGLASSES";
  if (weather.temp > 18) return "LIGHT LAYERS";
  return "WEAR LAYERS";
}

void centered(String s, int y, uint8_t size, uint16_t color) {
  tft.setTextSize(size); tft.setTextColor(color);
  int16_t x1,y1; uint16_t w,h;
  tft.getTextBounds(s, 0, y, &x1, &y1, &w, &h);
  tft.setCursor((240 - w) / 2, y); tft.print(s);
}

void statusScreen(const char* title, const char* detail, uint16_t color) {
  tft.fillScreen(BLACK);
  tft.drawCircle(120, 120, 105, DARK);
  centered(title, 95, 2, color);
  centered(detail, 130, 1, GRAY);
}

void drawWeather() {
  tft.fillScreen(BLACK);
  tft.drawCircle(120, 120, 118, DARK);
  centered("AMSTERDAM", 20, 1, AMBER);
  centered(condition(weather.code), 38, 1, GRAY);
  tft.drawFastHLine(30, 55, 180, DARK);

  String degrees = String((int)round(weather.temp)) + " C";
  centered(degrees, 70, 5, WHITE);
  centered("NOW", 122, 1, GRAY);

  tft.drawFastHLine(30, 140, 180, DARK);
  centered("WIND " + String((int)weather.wind) + " km/h   RAIN " + String(weather.rain) + "%", 152, 1, CYAN);

  tft.drawRoundRect(19, 176, 202, 43, 8, AMBER);
  centered("WHAT TO WEAR", 181, 1, AMBER);
  centered(advice(), 198, 1, weather.rain > 40 ? CYAN : GREEN);
}

bool fetchWeather() {
  HTTPClient http;
  http.setTimeout(12000);
  if (!http.begin(weatherURL)) return false;
  int result = http.GET();
  if (result != HTTP_CODE_OK) { Serial.printf("HTTP: %d\n", result); http.end(); return false; }
  DynamicJsonDocument doc(6144);
  DeserializationError err = deserializeJson(doc, http.getString());
  http.end();
  if (err) { Serial.println("JSON parse failed"); return false; }
  JsonObject current = doc["current_weather"];
  weather.temp = current["temperature"] | 0.0;
  weather.wind = current["windspeed"] | 0.0;
  weather.code = current["weathercode"] | 0;
  JsonArray precipitation = doc["hourly"]["precipitation_probability"];
  weather.rain = precipitation.size() > 0 ? (precipitation[0] | 0) : 0;
  weather.valid = true;
  Serial.printf("%.1f C, wind %.0f, rain %d%%\n", weather.temp, weather.wind, weather.rain);
  return true;
}

void connectWiFi() {
  statusScreen("CONNECTING", ssid, AMBER);
  WiFi.mode(WIFI_STA); WiFi.begin(ssid, password);
  for (int tries=0; WiFi.status()!=WL_CONNECTED && tries<30; tries++) { delay(500); Serial.print('.'); }
}

void setup() {
  Serial.begin(115200);
  pinMode(TFT_BL, OUTPUT); digitalWrite(TFT_BL, HIGH);
  tft.begin(); tft.setRotation(0); tft.fillScreen(BLACK);
  connectWiFi();
  if (WiFi.status() == WL_CONNECTED && fetchWeather()) { lastUpdate=millis(); drawWeather(); }
  else statusScreen("NO WEATHER", "Check Wi-Fi and credentials", RED);
}

void loop() {
  if (WiFi.status() != WL_CONNECTED) { connectWiFi(); return; }
  if (lastUpdate == 0 || millis() - lastUpdate >= UPDATE_MS) {
    if (fetchWeather()) { lastUpdate=millis(); drawWeather(); }
    else if (!weather.valid) statusScreen("NO WEATHER", "Open-Meteo unavailable", RED);
  }
  delay(1000);
}