Deviant Weather User Guide
See how today's weather departs from what's normal for each place, date, and hour, with trend charts, a 10-day outlook, and warnings when conditions are far from normal.
Table of Contents
Basic Usage
How do I add locations to the app?
Tap the "+" button in the top toolbar (or, on first launch, "Search for a City"). Type a city name and tap a result. It's marked "Added" and the search stays open, so you can add several places in a row; tap "Done" when you're finished. To add where you are now, tap "Use Current Location". You can save up to 10 locations, and the search shows how many you've used.
How do I manage my saved locations?
Tap a location to see its full details. Swipe left on a location to delete it (you'll be asked to confirm). To change the order, tap the pencil button, drag the locations into place, and tap the checkmark. Touch and hold a location for more options: Refresh, Share Weather, Copy Weather, Move to Top, and Delete.
How do I refresh the weather?
Pull down on the list to refresh every location, or pull down on a location's screen to refresh just that one. A location's screen also refreshes on its own when you open it, or come back to the app, if its weather is more than 30 minutes old. The bottom of the screen shows when it was last updated.
Can I use Deviant Weather on iPad and from the Home Screen?
Yes. On iPad, your locations appear in a sidebar beside the selected location's details. On iPhone and iPad, touch and hold the app icon for quick actions: "Add Location" and your first three locations. Your locations sync through iCloud to your other devices signed in to the same Apple Account.
Understanding Temperature Deviance
What is temperature deviance?
Temperature deviance shows how far the current temperature is from what is normal for that location, on this date, at this hour. Each location's screen leads with it, for example "+9°F above normal", with the actual temperature, its normal ("Normally 63°F"), the conditions, and the feels-like temperature beside it. Red means warmer than normal, blue means cooler, and gray means the temperature is within the normal range.
How is deviance calculated?
The app subtracts the normal for the current hour from the current reading. For example, if it's 72°F and the normal for this hour is 63°F, the deviance is +9°F (warmer). Comparing against the hour's own normal means a cool morning isn't measured against the warmth of the afternoon. When the reading and the normal round to the same value, the app says the temperature is at normal for this date.
What do "Slightly", "Notably", "Much", and "Far" mean?
They describe how unusual a reading is for that place and date. Slightly: far enough from normal to notice. Notably: clearly unusual for this date. Much: well away from normal, a reading the place sees only occasionally on this date. Far: among the most extreme readings the place sees on this date. Bolder text means further from normal. The thresholds adapt to each place, because four degrees off normal is routine in a continental interior but unusual on a temperate coast. Readings close to normal are listed as "within normal range".
Does the app compare more than temperature?
Yes. Feels-like temperature, dew point, humidity, pressure, wind speed, wind gusts, cloud cover, UV index, precipitation, and precipitation chance are each compared with their normals too. Only temperature and feels-like temperature use red and blue. The other readings state their direction in words, such as "Much higher cloud cover than normal", so more cloud never looks "hot".
What are the warnings at the top of a location's screen?
Deviant Weather shows a warning when conditions are exceptional for the date. "Far outside normal for this date" means the temperature or feels-like temperature is more than 20°F (11°C) from normal, or a downpour is three times the normal rain, confirmed on two refreshes. "Far from normal for hours" means a reading graded Far has lasted three hours or more. "Two readings at once" means two unrelated readings have both been Much or Far from normal for three hours or more. The location's card in the list shows the same warning, and the warning goes away once conditions return toward normal.
Weather Data
Where does the weather data come from?
All weather data comes from Apple Weather (WeatherKit): current conditions, the hourly and 10-day forecasts, the past 30 days, and the history used to work out what is normal. The app doesn't use any other weather service.
What time period do the historical normals cover?
Temperature normals come from Apple Weather's climate statistics for each location, hour by hour, built from its full historical record. Normals for the other readings are worked out on your device from Apple Weather's history for the same date in recent years, back to 2022, and need at least two years of data. A date without enough history shows "No historical comparison yet" instead of an estimate. The "on record" chart on each location's screen shows the individual years behind the normal.
How often is the data updated?
Current conditions update whenever a location refreshes: when you pull down to refresh, or automatically when you open a location whose weather is more than 30 minutes old. Charts are reused for 5 to 30 minutes, and the 10-day forecast for an hour, before they're fetched again. Normals change slowly, so they're kept for up to 30 days.
Features and Display
What's shown on each location card?
Each card shows the location's name, current temperature, and conditions, then one line for each reading that's away from normal, strongest first. If more than five readings are away from normal, the card says how many more there are. Readings within the normal range share a single gray line at the bottom. If a warning is active, it appears at the top of the card.
What's on a location's screen?
From the top: how far the temperature is from normal, with the actual temperature, its normal, conditions, and feels-like; any active warning; the Temperature Trend chart; a card for each other reading the location's card flagged; the Pressure Trend and Wind Speed Trend charts; the 10-day forecast, comparing each day's high with its normal high; "on record", showing each past year's high for today's date beside today's forecast high; and Last 30 Days, showing how far each day's high was from its normal, including any run of days above or below normal.
What do the different chart colors mean?
On the Temperature Trend chart, the purple line is the temperature over the past and next 12 hours, and the gray dashed line is a normal day, hour by hour. Red shading marks hours warmer than normal and blue shading marks hours cooler than normal. The black dot is now, and the other dot is the normal for this hour, joined to it by a dashed line. On the pressure and wind charts, the purple line is the reading and the normal is marked in gray. In the 10-day forecast and Last 30 Days, red and blue show how far each day's high is from normal, with deeper color meaning further from normal. Tap "Show as Table" under a chart to read its values as a list. Settings > About > How to Read This explains every color and mark.
Can I get weather alerts?
Deviant Weather doesn't show official government weather alerts, such as watches and warnings. Use Apple Weather or your local weather authority for those. Instead, the app shows its own warnings when conditions are far from normal for the date (see "What are the warnings at the top of a location's screen?").
Can I share a location's weather?
Yes. Touch and hold a location in the list, then tap "Share Weather" or "Copy Weather". This shares the location's name, temperature, and conditions, plus the readings that are away from normal.
Settings and Preferences
What unit options are available?
Temperature: Fahrenheit or Celsius. Precipitation: inches or millimeters. Wind Speed: mph, km/h, or m/s. Pressure: inHg, hPa, or mmHg. Distance: miles or kilometers. To change them, tap the gear button in the top toolbar to open Settings. Your settings sync to your other devices through iCloud.
What other settings are available?
Settings > Display: Show Confidence Badges adds a High, Medium, or Low badge beside each reading, showing how reliable its normal is; Haptic Feedback turns the app's taps on or off. Settings > Privacy: Anonymous Usage Analytics records usage on your device only. Settings > Data: Clear Cache, Delete All Data, Reset All Settings, and Export Diagnostics. Settings > About: How to Read This, links to support and the privacy policy, and the app's version and build.
Where can I learn what the colors and words mean?
Go to Settings > About > How to Read This. It explains what the app compares against, what each color and chart mark means, the four levels from Slightly to Far, and where the normals come from.
Troubleshooting
What should I do if weather data won't load?
Check your internet connection; when you're offline, an offline symbol appears in the top bar of a location's screen. Pull down to refresh. If a chart or the forecast couldn't load, its card says so; pull down to try again. "Service busy" means Apple Weather is briefly limiting requests, so wait a few minutes and refresh. Until fresh data arrives, the app keeps showing the last weather it loaded.
Why does a new location say "No historical comparison yet"?
Deviant Weather builds a location's normals the first time you add it, which can take a refresh or two. Pull down to refresh after a minute. A few places and dates don't have enough history to compare against; for those, the app shows the weather without a comparison rather than guessing.
Why don't my locations appear on my other devices?
Locations sync through iCloud. Make sure each device is signed in to iCloud with the same Apple Account and has an internet connection. If syncing has a problem, Settings > Data shows a message explaining it, such as being signed out of iCloud or iCloud storage being full.
How is my privacy protected?
Deviant Weather talks only to Apple: Apple Weather for weather data, iCloud to sync your locations and settings, and Apple's place search. Locations are rounded to about 1 km before they're stored or synced. The app asks for your location only when you tap "Use Current Location", and you can always search for places by name instead. Nothing is shared with third parties. Usage analytics and crash reports stay on your device unless you choose Settings > Data > Export Diagnostics.