Yes what Mandrake said.... But there are several differences between Ecowitt.net and AmbientWeather.net. Ecowitt.net does not yet have integration with IFTTT nor Google Assistant nor Amazon Alexa. Ecowitt.net also does not have data down capabilities. Ecowitt.net does not have a published API so 3rd party software options do not work like; Saratoga Weather Template, WordPress Weather Station, and a Python script to publish data to CWOP are all some examples that have come out to use Ambientweather.net.
Ecowitt has said they are working on adding an API to enable these features. But it will be a long time (no schedule nor ETA for what that means.) Even if Ecowitt comes out with their API you'll still be reliant on these 3rd party developers to update their offerings to tie into Ecowitt.net.
However Ecowitt.net does have a map (no Ambientweather.net map) and nicer looking layout than Ambientweather.net as in some ways it does look like newer version of the same service. Also selecting a previous date to look at is easier with Ecowitt.net because it has a calendar for date selection rather than an awkward forwards and back buttons.
How to upload to AmbientWeather.net from any Fine Offset clone station
But if you really want Ambientweather.net now there is a way to get it to work. All you need is one of two solutions. You need an ObserverIP (or similar device) with a Meteobridge that has added Ambient license. Or you need and ObserverIP (or similar device) with a WeatherBridge. A WeatherBridge is basically A Meteobridge that already has the required Ambientweather.net license and is sold by Ambient Weather. However you can build your own Meteobridge and then add the Ambientweather.net license ($150). So these are two solutions that amount to basically the same thing, just different ways to end up with the same solution. Since this device has no frequency as it gets data from your ObserverIP (or similar device) it will work with your setup that is a non Ambient branded clone of a Fine Offset station (Maplin, Aercus, Conrad, Froggit, Misol...etc). So this is a solution for whatever frequency you have as it won't matter. Now you can't just order an Ambient ObserverIP as that only comes with 915 MHz. So you need an Aercus WeatherLogger which is basically the same thing but uses 433 MHz. Even if you have a different branded 433 MHz station the Aercus will work. Or maybe your branded reseller has this device to sell you. But if you need 868 MHz or you can't buy the Aercus or similar from your reseller then you can buy the Ecowitt version with any frequency you specify.
* UPDATE - March 2020 - Ambientweather.net license for Meteobridge has new lower price, now just $100
Outdoor sensor array > ObserverIP (or similar device w/ your frequency) > WeatherBridge (or Meteobridge w/ Ambient license add-on) > Ambientweather.net
* The ObserverIP (or similar device) also requires a WH32B or similar device with your frequency to give you barometric pressure (and indoor temperature and humidity). This is usually sold with the ObserverIP (or similar device) as a set but you need to be sure. You need this part. It is not optional.
It may seem like a crazy investment to just get your station data over to AmbientWeather.net....but there is a whole lot more gained by having a Meteobridge or WeatherBridge. You can then do an incredible amount of extra things with your station. You can publish to just about every online weather service known (I'm sending data to 10 online services...but there are yet others that I don't send to). Some of these are the popular CWOP, PWSweather, AWEKAS, WeatherCloud, MetOffice WOW, and of course WU and many others. You can use it to send data to your own website with many different available popular templates. You can send your data to SQL database for safe keeping of your data as a backup or for future use or for use in your own analysis or for future software import. You can send data over to Weather-Display software. You can use it to send your camera to WU and to Meteobridge's servers for then hosting at other places (with embedded weather data). It is also a great way to have remote access giving you a remote console anywhere without dealing with router ports and it is an encrypted https connection. Add custom triggers to send email and/or Twitter. So you gain the capabilities of having a very powerful weather station.
Realize you can have both Ambientweather.net AND Ecowitt.net at the same time as I do. All you need is to also have an Ecowitt GW1000 (which you order with your frequency.)
Outdoor sensor array > Ecowitt GW1000 > Ecowitt.net