Compare day length
compare_day_lengthRead-only
Use this when the user asks for day length differences and average change per day between two local dates, or the solstices and equinoxes of a year. Returns daylight duration for each date and signed changes. Limits: cities with population 50,000+ (plus Tromso), dates/years 1900–2100, flat sea-level horizon; use either date_a and date_b or year, and not both. Does not forecast weather.
Input Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| city | Yes | City name, for example New York. Cities with population 50,000+ are supported; the largest same-name match is used. | |
| year | No | Year whose equinox and solstice local dates to compare, for example 2026. Omit date_a/date_b. | |
| state | No | Optional US state name or abbreviation, for example NY or New York. | |
| date_a | No | First local date for a two-date comparison, for example 2026-03-20. Required with date_b; omit with year. | |
| date_b | No | Second local date, for example 2026-06-21. Required with date_a; omit with year. | |
| country | No | Optional country name or two-letter code to narrow the match, for example US. |
Output Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| blue | No | ||
| date | No | ||
| days | No | ||
| mode | Yes | ||
| civil | No | ||
| golden | No | ||
| period | No | ||
| sunset | No | ||
| values | No | ||
| changes | No | ||
| preview | No | ||
| request | Yes | ||
| sunrise | No | ||
| location | Yes | ||
| nautical | No | ||
| timeZone | No | ||
| dayLength | No | ||
| dayStatus | No | ||
| downloads | No | ||
| solarNoon | No | ||
| startDate | No | ||
| eventCount | No | ||
| definitions | Yes | ||
| limitations | Yes | ||
| astronomical | No | ||
| sunsetAzimuth | No | ||
| sunriseAzimuth | No | ||
| dayLengthSeconds | No |