Build an ESP32 weather station with a live cloud dashboard

A weather station is the project that makes a maker check a dashboard every morning. This one measures the weather where you actually are — temperature, humidity, and the barometric pressure that warns of an incoming storm — with a single BME280, and streams it to a live dashboard you open from your phone anywhere. No regional-forecast API guessing at your microclimate; the pressure on your own balcony, charted.

Most ESP32 weather-station tutorials stop one step short: they read the sensor and print it to the Serial Monitor or a tiny OLED, then wave at “connect it to the cloud” as a next step. This one is the cloud step, done properly — over plain HTTPS to your own Cloudflare account, no MQTT broker and no legacy freemium platform holding your history.

Why the BME280

The default two-in-one sensor, the DHT22, measures temperature and humidity and nothing else. The BME280 measures those plus barometric pressure, from the same small I2C part — and pressure is what earns the name “weather station.” A steadily falling barometer is the oldest reliable storm signal there is, hours ahead of the clouds. The BME280 is also more accurate than a DHT22 and speaks clean I2C instead of the DHT’s slow, occasionally-flaky one-wire timing. For a few cents more, it’s the sensor every serious build uses.

(One caution when buying: the BMP280 is the cheaper sibling with no humidity. For a weather station you want the BME — the E has humidity.)

What you’ll need

• An ESP32 dev board (any common DevKit variant).
• A BME280 breakout (I2C version — most are).
• Four jumper wires.
• The Arduino IDE with the ESP32 board package, the Nodrix library, and Adafruit’s BME280 library (it pulls in the Adafruit Unified Sensor library), from the Library Manager.
• A nodrix instance with a project and a project token.

Wiring

I2C, four wires, no analog:

Mount the BME280 away from the ESP32 on a short lead. The board’s own heat will bias the temperature reading if the sensor sits right against it — a couple of centimetres and some airflow fixes it.

The firmware

Read three values, send three variables, on a gentle cadence — weather moves slowly. The nodrix Arduino library handles the connection.

#include <Nodrix.h>
#include <Adafruit_BME280.h>

const char* WIFI_SSID = "your-ssid";
const char* WIFI_PASS = "your-password";
const char* HOST      = "nodrix.you.workers.dev";
const char* TOKEN     = "tok_your_project_token";

Adafruit_BME280 bme;

void setup() {
  bme.begin(0x76);          // some breakouts are at 0x77
  Nodrix.begin(WIFI_SSID, WIFI_PASS, HOST, TOKEN);
}

void loop() {
  Nodrix.run();

  static unsigned long lastReading = 0;
  if (millis() - lastReading >= 60000) {
    lastReading = millis();
    Nodrix.send("temperature", bme.readTemperature());
    Nodrix.send("humidity", bme.readHumidity());
    Nodrix.send("pressure", bme.readPressure() / 100.0F);   // Pa → hPa
  }
}

Worth understanding rather than copying:

• Pressure in hPa. The BME280 reports pascals; dividing by 100 gives hectopascals (millibars), the unit weather reports use — sea-level pressure sits around 1013 hPa, so your readings should land near there once you account for altitude.
• A minute between readings is generous. Weather doesn’t change in seconds. On mains power a minute is fine; on a battery you’d stretch it to 5–15 minutes and deep-sleep between.
• Check the I2C address. BME280 breakouts are at 0x76 or 0x77 depending on the board — if begin() fails, try the other.
• Pin TLS before you ship. Nodrix.begin() connects encrypted but unverified on first run; add Nodrix.setCACert() for production, covered in Connect an ESP32 over HTTPS.

Build the dashboard

The pressure chart is the one to watch. Absolute pressure matters less than its slope: a slow rise means settling, fair weather; a steady fall over a few hours is the classic sign of an approaching low and likely rain. Once you’ve watched it for a week against what the sky actually did, you’ll read an incoming front off that line before any app tells you.

Add the storm alert

Weather stations reward one good automation. A rapid pressure drop is the signal worth a notification: trigger on a new pressure reading, and alert when it falls meaningfully below where it sat a few hours ago (a threshold around 1000 hPa is a reasonable absolute floor for “weather coming” in many regions; tune it to yours). Action: Telegram — “Pressure dropping, {{value}} hPa — weather likely turning.” Swap the channel for Discord or SMS without touching the logic, per ESP32 notifications.

Going further

• Take it outside on a battery. Deep sleep makes an outdoor node last months; house it in a vented radiation shield to keep sun and rain off the sensor — see ESP32 battery life.
• Add rain and wind. A tipping-bucket gauge (a counted reed switch), an anemometer, and a wind vane each add a variable and a widget without changing the loop’s shape.
• Compare to the forecast. Pull your own history through the read API and chart it against a weather service’s numbers — your microclimate almost never matches the regional forecast exactly, and the gap is the interesting part.
• Run several stations. Sun and shade, indoors and out, ground and roof — each node reports its own variables to one dashboard.

Notes

• Your microclimate, not a regional guess. The sensor measures your location; the API can’t.
• No broker, no legacy cloud. HTTPS to your own Cloudflare account — no MQTT, no ThingSpeak or Blynk caps, history that stays yours behind the read API.
• Battery-friendly by design. Slow weather plus deep sleep equals months on a cell.