#include <SPI.h>
#include <Ethernet.h>

// Enter a MAC address for your controller below.
// Newer Ethernet shields have a MAC address printed on a sticker on the shield
byte mac[] = {my mac };
char serverName[] = "api.weather.gov";

// Initialize the Ethernet client library
// with the IP address and port of the server
// that you want to connect to (port 80 is default for HTTP):
EthernetClient client;

void setup() {
 // Open serial communications and wait for port to open:
   while (!Serial) {
    ; // wait for serial port to connect. Needed for Leonardo only

  // start the Ethernet connection:
  if (Ethernet.begin(mac) == 0) {
    Serial.println("Failed to configure Ethernet using DHCP");
    // no point in carrying on, so do nothing forevermore:
  // give the Ethernet shield a second to initialize:

  // if you get a connection, report back via serial:
  int ret = client.connect(serverName,443);
  if (ret==1) {
    // Make a HTTP request:
    client.println("GET /stations/KGSO/observations/latest");
    client.println("accept: application/geo+json,*/*");
    client.println("user-agent: arduino, mymail@asdf.com");
    client.println("host: api.weather.gov");
  else {
    // kf you didn't get a connection to the server:
    Serial.println("connection failed");

void loop()
  // if there are incoming bytes available
  // from the server, read them and print them:

  if (client.available()) {
    char c = client.read();

  // if the server's disconnected, stop the client:
  if (!client.connected()) {

    // do nothing forevermore:

When I run this I get:

connecting... connected


Why don't I get data? I thought it was about the header info. But I looked at https://www.weather.gov/documentation/services-web-api#/ and it doesn't say it needs much.

  • what happens if you remove the last if block? – jsotola Jan 19 at 8:07
  • connecting... connected – Jason William Stone Jan 19 at 13:11
  • Yes I think Juraj has the answer (thanks): Can't get there from here. Maybe that's an excuse to get a raspberry pi. – Jason William Stone Jan 19 at 14:44

The Ethernet library doesn't support secure connection (so called SSL, but TLS now). To connect to a secure HTTP transport HTTPS the secure connection is necessary. The AVR MCU don't have the computing power to compute the security keys. And for less popular 32bit MCU nobody created a 'SSL' implementation for Ethernet library yet.

esp8266, esp32, MKR1010, Uno WiFi, Nano 33 IoT can do HTTPS, but all only over WiFi as far as I know.

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