I don't have such a phone to use an app :o). but I am sure there must be a weather app that will give you that info.

Oh why do we depend so much on these gadjets ! I can always tell if there's a frost on the way. I just step outside and feel the air.

There are very local weather forecasts on line now that are pretty accurate - you don't need an app.

Ok. I understand. It’s just being a busy mum and with my dahlia’s potted up in my summerhouse I dread to think that one frost can be the end of it all! I’m often not home till late and could do with a reminder to take them indoors if a cold night is forecast. That’s all.

Write yourself a note to check the forecast you'll see when you come in? The old fashioned solutions still work.

download the BBC weather app and set it for your area.All you have to do then is remember to check it during the day - it won't alert you to a frost, but you will be able to see by the temperatures whether there's going to be one.

Otherwise, there is an app called Weather Underground: Forecast (in the States, not sure if there's a UK version) available for iphones - that does do alerts, not specifically for frost, but for cold weather, freezes and adverse weather events. There doesn't seem to be anything like it for Android phones.

https://itunes.apple.com/us/app/weather-underground-radar/id486154808?mt=8

Thanks Bamboo. Will have a look.