Ecowitt.net has been designed to receive your 1 minute data for live dashboard view only. But it only retains history in 5 minute increments for use in the data charts and graphs. That is just the way it was designed. It isn't any different than how Weather Underground works where there is Rapidfire 16 second updates for the dashboard and then only 5 minute data retention increments.
If you want to retain data in 1 minute increments then you need to implement your own data retention process. There are several ways to do this, and not limited to only these I'm about to name. You can upload to PWSweather.com, you can save data to SQL, you can save and view data using 3rd party weather software (Meteobridge, WeeWx or Weather-Display), or you can upload to personal website. These solutions require additional hardware and software.
I'm saving to my own SQL database. I'm doing it in 5 minute increments. I could save in 15 second increments if I wanted or other custom amounts of time. But for most historical purposes and analysis and reporting and graphing, 5 minute data is sufficient. Which is why it is a almost a standard accepted practice. Why grow and deal with bigger databases than is necessary? If you have your dataset variables configured correctly you aren't missing data with 5 minute increments. I'm not saving a live data snapshot every 5 minutes, rather every 5 minutes you save peak wind for the prior few minutes. You can make this be anything you want, even averages if your prefer, and you can treat each sensor with its own attributes. Same goes for temperature and humidity.... etc. Most other weather services that only retain 5 minute data work this way.
