In an earlier version, this applet was said to offer five-day forecasts.
Would it be possible to restore this setting?
The weather information comes from openweathermap via their free opensource plan - so we can only supply the data supplied by them. If they choose to vary the duration or other then that is as much as we can share.
I do know openweather has paid for plans that can display historic information as well as longer duration stuff like 30 days.
As the developer of the applet we have not paid for these extended services. We don’t know how that information is transmitted and thus what changes (if any) the applet needs to do to accommodate.
[Extremely OT]
but … is a 30 days forecast reliable? Here, our Air Force only shows 4 days forecasts
Thank you, @fossfreedom.
Precisely, the reason I made this request is because OpenWather’s free package does provide five-day forecasts and Cinnamon’s “Weather” applet provides 8-day forecasts, again with OpenWeather.
But I agree with @puffettacicciottella, five days is enough to have a trend. 
I’ve noticed on openweather it isnt consistent what timespan you can get.
In my area I see 3 days worth of stuff, and others 4 or 5 days.
I havent seen 8 days but I suspect that might be due to an agreement (the api key used) linux mint has reached with openweather.
OK, thanks for the info.
This being said, UB is worth LM.
It too deserves such an agreement, doesn’t it ?