Does the weather affect your sleep? Here is how to check with your own data
Rain, clear skies and the hottest or coldest days can line up with your sleep and movement, and Daylumen checks those pairings against your own Apple Health history once you switch on its optional weather. It needs at least five days of a given kind of weather before it says anything, describes patterns rather than causes, and does not pair weather with the energy you log by hand.
The general answer is "it depends on the person". The useful answer is narrower: on the days it rained where you live, did you sleep differently from your usual? That is a question about your own records.
Sources: Daylumen 1.12.0 as released on the App Store, Daylumen's privacy policy (last updated October 11, 2026) and Apple's WeatherKit page (developer.apple.com/weatherkit), all checked 2026-10-14.
Why this question has two answers
People search for whether hot weather ruins sleep, whether cold weather makes them tired, and why rainy days make them sleepy. These are real experiences. The honest general answer is that it varies from person to person and from place to place, and a web page cannot tell you which group you are in.
The question you can settle is about you: on the rainy, clear, hottest or coldest days of the last few months, did your sleep or your movement differ from your own usual range? Daylumen is built to answer that one, using the sleep and step data already in Apple Health plus a daily weather record for your location.
What Daylumen compares the weather with
| Weather on the day | Compared with | Before it says anything |
|---|---|---|
| Rainy day (1 mm of precipitation or more) | Steps, and hours of sleep | At least 5 rainy days with data |
| Clear day (as classed by Apple Weather) | Steps, and hours of sleep | At least 5 clear days with data |
| Hottest days (roughly the top fifth of daily highs in the period) | Hours of sleep, and heart rate variability if a device writes it to Apple Health | At least 10 days of temperature data, 5 of them hot |
| Coldest days (roughly the bottom fifth of daily highs) | Steps | At least 10 days of temperature data, 5 of them cold |
A result is a plain sentence such as "On rainy days, you sleep more", with the size of the difference and a reminder that it is your own pattern, not a rule. Hot and cold are relative to the period Daylumen has weather for, so it never quotes an absolute temperature.
Weather never changes your baseline. Your usual range for sleep and steps is computed from Apple Health alone; the weather only sorts days into groups so they can be compared. Five qualifying days is the minimum, not a guarantee: if the difference is small, Daylumen stays quiet.
How to switch weather on
- Open Settings in Daylumen and tap Weather. Until it is on, the row reads "Add rain and temperature to your days".
- Turn the switch on. Daylumen asks once for your approximate location. It needs only a rough position, about city level.
- If you decline or location fails, pick a city. A built-in list of about forty cities is offered instead. You can change the city later from the same screen.
- Let it backfill. Daylumen fetches daily weather for the past 180 days for that spot, so the comparison does not start from zero if Apple Health already has history.
Where your location goes
According to the privacy policy, the coordinates are rounded to about 0.1 degree, roughly city level, and sent to Apple Weather (WeatherKit) for the lookup. They are not uploaded to Daylumen's servers. On the device Daylumen keeps the date, the weather values and a city name for display, never an exact position or a trail of where you went. Apple's WeatherKit page says location is used only to provide forecasts, is not associated with personally identifiable information and is not tracked between requests (checked 2026-10-14).
Turning the switch off stops further lookups. Weather already stored stays on the device, so switching it back on does not fetch the same days again.
What about energy, and feeling tired when it rains?
Daylumen lets you log mood, energy and stress in a few taps. But the weather pairings it computes are the ones in the table: sleep, steps and heart rate variability. It does not currently pair the weather with the energy you log, so if your question is whether rain makes you tired, the app will not answer that directly. The closest thing it offers is steps on rainy days, which for many people is where a rainy-day slump shows up first.
What it will not do
- It does not forecast, and it gives no tips for sleeping through a heatwave. It reads what happened.
- It does not diagnose. A pattern between heat and short sleep is a pattern in your records, not a medical finding.
- Weather is for one place. On days you travel, the weather record is for your usual location, not where you slept.
- With no sleep source in Apple Health the sleep pairings cannot be made. The steps pairings still work from the iPhone alone.
Frequently asked questions
Do I need an Apple Watch for this?
No. Steps come from the iPhone, and sleep can come from any source that writes to Apple Health. Only the heart rate variability pairing needs a device that records it.
Does the weather change my personal baseline?
No. The baseline is computed from Apple Health data only. Weather is used to group days, not to shift what counts as usual for you.
How long after switching on will I see anything?
Daylumen backfills 180 days of weather, so if Apple Health already holds a few months of sleep or steps, a pairing can appear after the next analysis. Otherwise it waits until a kind of weather has at least five days with data.
Is weather a paid feature?
Switching weather on is not itself paid. Daylumen is free to download; the full overview of all connections is one of the features unlocked by the one-time purchase, and the daily reading stays free.
Daylumen reads the health data already on your iPhone and tells you what it means for today.
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