Boto CloudWatch Not returning results from AWS Web Console, and Results are There

Question

I'm using boto to look for cloudwatch usage metrics from some of my machines. I can't seem to get it to return any results. The returned list is always empty.

I have checked in the web console and there are metrics for the timeframe I'm searching.

start: 2016-06-07 23:54:55.876006 end:2016-06-08 00:54:55.876006 i-5ea3633 {'InstanceID': 'i-5ea3633'} CloudWatchConnection:monitoring.us-west-2.amazonaws.com

However, cloudwatch doesn't return anything to my python script.

ec2_conn = boto.ec2.cloudwatch.connect_to_region(region,
                                  aws_access_key_id=creds.access_key, 
                                  aws_secret_access_key=creds.secret_key)

intDimentions = {"InstanceID":str(id)}
end = datetime.datetime.utcnow()
start = end - datetime.timedelta(hours=1)
print start,end,id,intDimentions,ec2_conn
metrics = ec2_conn.get_metric_statistics(60, start, end, "CPUUtilization", "AWS/EC2", "Average", dimensions=intDimentions)
print metrics