NOAA Solar Calculator
Calculate local sunrise, sunset, solar noon, and day length using NOAA-style solar equations.
What is a NOAA calculator?
A NOAA calculator usually refers to a solar position calculator based on formulas published by the National Oceanic and Atmospheric Administration (NOAA). These formulas estimate important solar events for a specific date and location, including sunrise, sunset, and solar noon.
People use NOAA-style calculations for photography planning, gardening schedules, outdoor event timing, solar panel analysis, and educational astronomy projects. The model is practical and widely trusted for everyday planning.
How this NOAA solar calculator works
This page uses standard NOAA-inspired solar equations with:
- Fractional year angle derived from day-of-year,
- Equation of time to account for Earth’s orbital geometry,
- Solar declination to represent seasonal tilt effects,
- Hour angle at sunrise/sunset using a standard zenith of 90.833°.
From those values, it computes local solar noon and then sunrise/sunset times for your selected UTC offset and optional daylight saving time adjustment.
Inputs you need
- Date: The calendar date you want to analyze.
- Latitude: North is positive, south is negative.
- Longitude: East is positive, west is negative.
- UTC offset: Your local time zone relative to UTC.
- DST checkbox: Add one hour if daylight saving is active.
Understanding your results
Sunrise and sunset
Sunrise is when the top edge of the Sun becomes visible under standard atmospheric assumptions. Sunset is the reverse event in the evening. A small atmospheric refraction correction is included through the standard NOAA zenith value.
Solar noon
Solar noon is the moment the Sun reaches its highest altitude for that day at your location. It is often not exactly 12:00 PM clock time because of longitude position inside your time zone and the equation of time.
Day length
Day length is the estimated time between sunrise and sunset. It changes daily and depends strongly on latitude, especially in spring and fall at mid-to-high latitudes.
Important notes and limitations
- Results are approximate and intended for planning, not legal, aviation, or navigational use.
- Extreme latitudes may experience polar day or polar night, where sunrise or sunset may not occur on the selected date.
- Local terrain, elevation, weather, and atmospheric conditions can shift observed times by several minutes.
- If your region changes DST rules, verify your UTC offset and DST setting manually.
Practical uses for a NOAA calculator
- Photography: Plan shoots around sunrise, sunset, and golden-hour transitions.
- Solar energy: Estimate sunlight windows for panel productivity checks.
- Fitness and outdoor training: Schedule runs and rides around available daylight.
- Agriculture and gardening: Track seasonal daylight changes.
- Education: Demonstrate Earth tilt, declination, and seasonal cycles.
FAQ
Is this the same as the official NOAA web tool?
It is a NOAA-style implementation based on commonly published equations. Exact values may differ slightly from other tools depending on rounding, model settings, and atmospheric assumptions.
Why is solar noon not exactly 12:00?
Clock noon follows time zones; solar noon follows the Sun. Your longitude and the equation of time shift the Sun’s highest point away from 12:00 in many places.
Can I use this for polar regions?
Yes, but you may see “no sunrise” or “no sunset” for certain dates. That is expected behavior at high latitudes during parts of the year.