5G tested across America: It’s crazy fast — and a hot mess

Joanna Stern for The Wall Street Journal:Today’s forecast: 95 degrees and sunny with thunderstorms likely in the afternoon. No chance of 5G testing. One of the biggest findings of my multicity 5G review tour: The Samsung Galaxy S10 5G isn’t reliable in the summer — unless, well, you summer in Iceland. When I ran tests, the phone’s 5G often switched off due to overheating, leaving me with a 4G connection. Cellular carriers demo-ing or testing the phone have taken to coolin