I'm having two issues with your plugin.
1. With the 4.2 update I can't find my Location anymore, by entering the name in the pop-up search. No problems finding it with 4.1. I'ts Mali Losinj, Croatia. But I've copied the location code from 4.1 and seems to work fine.
2. The 4.2 version displays the same date for the next two forecast days, as for the current day. You can see what I mean here. I've edited the css a bit to fit the space and removed the 'day' word from forecast by deleting it from wp-forecast-show.php, on line 381. Not sure if that made it not work properly, but I've tried reinstalling and it didn't help.