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# Time zones and when a day closes

Reporting · For everyone · Updated 30 October 2026
Web version: https://www.affiliateos.ai/help/reporting/time-zones-day-close

Every report on AffiliateOS counts days in UTC, from midnight to midnight. The date picker names days by your computer's calendar, but the numbers for a day are always that date's UTC day. Today's numbers fill in as the day goes; a reversal that arrives later moves an earlier day at our next rebuild, a few hours later.

## Which day it lands on

Example: Pebble Rewards in Texas. On 29 October, Texas is five hours behind UTC.

| In Texas | In UTC | Counts on |
|---|---|---|
| 29 October, 2:06 PM: player `u_48213` taps Harbor Blocks | 29 October, 7:06 PM | 29 October |
| 29 October, 7:30 PM: the install comes in | 30 October, 12:30 AM | 30 October |

The click counts on the day of the tap, and the [conversion](https://www.affiliateos.ai/glossary#conversion) on the day we received it. Here they land on different days, so 29 October shows a click with no conversion and 30 October a conversion with no click. Over a week it mostly evens out; over one evening it doesn't.

## Where each screen draws the line

| Where | Days and times |
|---|---|
| **Dashboard** and **Offer Performance**, publishers and networks | UTC days. Weeks start on Monday, UTC. |
| Advertiser **Overview** | UTC days |
| **Conversions** | **From** and **To** are UTC dates. Each row's time shows in your browser's time zone. |
| **Flight Recorder** | Each row's time shows in your browser's time zone |
| The Reporting API | UTC. `performance/daily` days and `dashboard-report` buckets are UTC days. |
| Offer caps | The offer's own clock: **Capped for today** shows when it reopens, and `capResetsAt` gives that time in UTC |

> **On Conversions, To means the start of that day.** A date in **To** is read as midnight UTC at the start of that date, so the date itself is left out. To include all of 29 October, set **To** to 30 October.

## When a day closes

A UTC day is over at midnight UTC, but its numbers can still change:

- **Through the day,** today's numbers fill in as clicks and conversions arrive.
- **When a reversal arrives,** it is dated on its conversion's day, not the day it arrived. It lowers the period the conversion was earned in, so last week can drop after you've closed it.
- **Reversals of an earlier day** show in the daily totals at our next rebuild, a few hours later (we rebuild those days four times a day). On the **Conversions** screen they show at once, with the date they came in.

If you close your books on a day, export it after 03:00 UTC the next day, and match reversals that come in later on `action_id`. [Why our numbers and yours differ](https://www.affiliateos.ai/help/reporting/why-numbers-differ) covers the rest.

## For advertisers

Your **Overview** days are UTC days too. Separately, each event's `timestamp` is checked against the time we receive it: an event more than 48 hours either side is logged as `outside_window` and not charged. Send events as they happen, with the time they happened.