Netatmo switched certificate authorities from StartCom to Go Daddy. This is good news since Java recognizes Go Daddy as a valid certificate provider. That means https://github.com/openhab/openhab1-addons/wiki/Netatmo-Binding#missing-certificate-authority does not need to be done when Java is upgraded.
$ curl -v https://api.netatmo.com
* Rebuilt URL to: https://api.netatmo.com/
* Hostname was NOT found in DNS cache
* Trying 195.154.179.238...
* Connected to api.netatmo.com (195.154.179.238) port 443 (#0)
* successfully set certificate verify locations:
* CAfile: none
CApath: /etc/ssl/certs
* SSLv3, TLS handshake, Client hello (1):
* SSLv3, TLS handshake, Server hello (2):
* SSLv3, TLS handshake, CERT (11):
* SSLv3, TLS handshake, Server key exchange (12):
* SSLv3, TLS handshake, Server finished (14):
* SSLv3, TLS handshake, Client key exchange (16):
* SSLv3, TLS change cipher, Client hello (1):
* SSLv3, TLS handshake, Finished (20):
* SSLv3, TLS change cipher, Client hello (1):
* SSLv3, TLS handshake, Finished (20):
* SSL connection using TLSv1.2 / ECDHE-RSA-AES256-GCM-SHA384
* Server certificate:
* subject: OU=Domain Control Validated; CN=*.netatmo.com
* start date: 2016-12-15 15:28:01 GMT
* expire date: 2017-12-15 15:28:01 GMT
* subjectAltName: api.netatmo.com matched
* issuer: C=US; ST=Arizona; L=Scottsdale; O=GoDaddy.com, Inc.; OU=http://certs.godaddy.com/repository/; CN=Go Daddy Secure Certificate Authority - G2
* SSL certificate verify ok.