You can set level of the Werkzeug logger to ERROR, in that case only errors are logged:
import logging
log = logging.getLogger('werkzeug')
log.setLevel(logging.ERROR)
Here is a fully working example tested on OSX, Python 2.7.5, Flask 0.10.0:
from flask import Flask
app = Flask(__name__)
import logging
log = logging.getLogger('werkzeug')
log.setLevel(logging.ERROR)
@app.route("https://stackoverflow.com/")
def hello():
return "Hello World!"
if __name__ == "__main__":
app.run()