Bell Weather compares recent weather with every year on record at a nearby weather station. If something looks wrong, or you have a question this page doesn't answer, email **[[email protected]](mailto:[email protected])**. I read everything and usually reply within a few days. It helps to include the place you're asking about, the measure (mean temperature, precipitation, and so on), and a screenshot if you have one. ## Common questions ### Where does the data come from? Daily observations from NOAA's network of US weather stations, pulled through the Regional Climate Centers' ACIS service. Nothing is modelled or forecast. Every number in the app comes from a measurement someone took. ### Why is my town matched to a station somewhere else? Bell Weather needs a long, mostly complete record to compare against, and not every town has one. It looks for stations within about 60 km and prefers the longest record that's close by, with a small preference for airport stations, which tend to report most consistently. Cupertino, for example, gets Redwood City. You can pick a different station: tap the ⓘ next to the place in your Locations list. Each candidate shows how many years of usable data it has. More years means better comparisons. ### What does "Not enough usable history" mean? A year only counts if the station recorded nearly every day of the window you're looking at that year. Temperatures can tolerate a few missing days. Rain and snow totals can't, because a missed day might have been the storm. If too few years pass that test, the app says so rather than ranking against a thin record and producing subpar results. Try a different station, or a shorter window. ### Why don't the numbers include today? Stations report with a delay, usually a day and sometimes several. The date next to the window shows the last day the station has reported. Refreshing a location pulls the latest available data. ### What is "normal"? By default, every usable year in the station's record. You can switch to 1951–1980, 1991–2020 (NOAA's current official normals), or the last 15 years. The same stretch of weather can look ordinary against recent years and extreme against mid-century, and the app always shows which baseline you're on. ### Does it work outside the US? No. The stations and data are US-only. I'm exploring similar datasets in other countries. ### Does it work offline? Yes, once a place has loaded. Records are stored on your device and updated when you're back online. ### Do my places sync between devices? Yes, through iCloud, if you're signed in. Nothing else leaves your device except the requests for station data. ## Privacy Bell Weather has no accounts, no analytics and no ads. If you use your current location, it's rounded to about a kilometer (~0.6 miles) and used only to find nearby stations. The full policy is here: [Privacy Policy for Bell Weather](https://jonathankizer.com/Garden/Apps/Privacy+Policy+for+Bell+Weather).