> ## Documentation Index
> Fetch the complete documentation index at: https://docs.anlytic.com/llms.txt
> Use this file to discover all available pages before exploring further.

# DayOfYear

Converts a date to the number day of the year, from 1 (Jan 1) to 365 (Dec 31). Accounts for leap years.

**Category:** `date`

**Syntax:**

```
DayOfYear([date], |timezone|)
```

**Returns:** `IntColumn`

**Context Filtering:** ✓ Yes

## Parameters

| Name       | Type               | Required | Description                                              |
| ---------- | ------------------ | -------- | -------------------------------------------------------- |
| `date`     | `column\|datetime` | ✓ Yes    | The date or column of date values to evaluate.           |
| `timezone` | `text`             | ✗ No     | Optional IANA time zone name (e.g., "Europe/Amsterdam"). |

**Allowed Column Types:** DATETIME, DATE

## Validation

* Minimum parameters: 1
* Maximum parameters: 2

## Examples

```
DayOfYear(Date("2023-01-01"))
```

Converts Jan 1, 2023 to the number day of the year.
**Result:** `1`

```
DayOfYear(Date("2023-12-31"))
```

Converts Dec 31, 2023 to the number day of the year.
**Result:** `365`

```
DayOfYear(Date("2024-12-31"))
```

Converts Dec 31, 2024 (leap year) to the number day of the year.
**Result:** `366`

```
DayOfYear(Date("2023-01-03 02:00:00Z"), "Europe/Amsterdam")
```

Converts Jan 3, 2023 02:00:00Z to the number day of the year in New York.
**Result:** `2`