Solunar Fishing Peak Time Calculator

Enter your latitude, longitude, moon phase, and month to calculate solunar major and minor fishing periods, a solunar activity index, and your best times to fish.

Created by Luis GonzalezLast updated: May 9, 2026

How to Use This Calculator

1
Enter Latitude
Provide the latitude of your fishing location in degrees (e.g., 40.7 for New York). Use negative values for the Southern Hemisphere.
2
Enter Longitude
Input the longitude of your fishing location in degrees (e.g., -74.0 for New York). Use negative values for locations west of the prime meridian.
3
Specify Moon Phase
Indicate the current moon phase as a percentage (0% = New Moon, 100% = Full Moon). New and Full moons are generally associated with stronger solunar activity.
4
Input Current Hour of Day
Enter the current or planned fishing hour in 24-hour format (0-23). This helps determine if you are currently within a peak solunar period.
5
Select Month
Choose the current month from the dropdown menu, as seasonal factors can influence solunar predictions.
6
Review your results
The calculator will display the Solunar Index, major and minor feeding periods, and your current hour's status.

Example Calculation

An angler in New York (Latitude 40.7°, Longitude -74.0°) plans to fish in June at 6 AM during a Quarter Moon (50% phase).

Latitude (°)

40.7

Longitude (°)

-74.0

Moon Phase (%)

Current Hour of Day (h (0–23))

Month

June

Results

5.9 / 10

Tips

Prioritize Major Periods

Major solunar periods, typically lasting about 2 hours around the lunar transit (moon directly overhead or underfoot), are generally considered the most active feeding times. Plan your fishing trips to coincide with these windows for best results.

Combine Solunar with Local Knowledge

While solunar theory provides a general guide, always integrate it with local knowledge of fish species behavior, seasonal patterns, water temperatures, and specific tides. No single factor guarantees success, but a combination of insights increases your odds.

Observe Barometric Pressure

Stable or rising barometric pressure often corresponds with active fish feeding. Sudden drops in pressure, often associated with approaching storms, can make fish less active, even during peak solunar periods.

Predicting the Bite: Your Solunar Fishing Peak Time Calculator

For anglers seeking an edge, solunar theory offers a fascinating approach to predicting optimal fishing times by correlating fish activity with the moon and sun's positions. This Solunar Fishing Peak Time Calculator helps you pinpoint major and minor feeding periods for any location and month, providing a Solunar Index to guide your expeditions. While a degree of skepticism surrounds its scientific rigor, many experienced fishermen swear by solunar charts, reporting improved catch rates during predicted peak times, especially around new and full moons, which are associated with the strongest tidal forces.

The Celestial Mechanics Behind Fish Activity

Solunar theory posits that the gravitational forces of the moon and sun, which cause tides, also influence the feeding and activity patterns of fish and wildlife. The calculator's logic determines "major" periods (around lunar transit and anti-transit) and "minor" periods (when the moon is on the horizon), alongside a Solunar Index that rates overall activity. This index is influenced by moon phase, season, and latitude, providing a comprehensive prediction.

The approximate lunar transit hour is calculated based on the moon phase:

lunar transit hour = (12 - (moon phase / 100) × 12 + 24) % 24
anti-transit hour = (lunar transit hour + 12) % 24
minor period 1 hour = (lunar transit hour + 6) % 24
minor period 2 hour = (lunar transit hour + 18) % 24

A solunar index combines the phase score, seasonal multiplier, and latitude factor to give an overall activity rating from 0-10.

💡 For practical fishing setup, our Float & Bobber Depth Setting Calculator can help you present your bait at the ideal depth.

Identifying Peak Fishing Times for a New York Angler

Let's assist an angler in New York (Latitude 40.7°, Longitude -74.0°) who plans to fish in June at 6 AM during a Quarter Moon (50% phase).

Input location and moon phase:
- Latitude: 40.7°
- Longitude: -74.0°
- Moon Phase: 50% (Quarter Moon)
- Month: June
- Current Hour: 6 AM
Calculate Lunar Transit Hours:
- lunar transit hour = (12 - (50 / 100) × 12 + 24) % 24 = (12 - 6 + 24) % 24 = 30 % 24 = 6 AM
- anti-transit hour = (6 + 12) % 24 = 18 PM (6 PM)
- Minor periods would be around 12 PM and 12 AM.
Determine Current Hour Status:
- Since the user's current hour (6 AM) matches the lunar transit hour, the current period is a "Major solunar period".
Calculate Solunar Index:
- The index combines moon phase influence (moderate for quarter moon), season (Summer multiplier), and latitude factor. For these inputs, the calculated Solunar Index is 5.9/10, indicating "Fair" conditions overall, but the current hour is a "Major solunar period".

This means that despite moderate overall conditions, the current time of 6 AM is a prime activity window according to solunar theory.

💡 To optimize your gear for different fishing conditions, our Fly Line Weight Recommendation Calculator can help you select the right line for your rod and target species.

Factors Influencing Fish Activity and Feeding

While solunar theory provides a fascinating framework, successful fishing demands considering a broader array of environmental factors that significantly influence fish activity. Water temperature is paramount; most fish species have optimal temperature ranges for feeding, and deviations can make them sluggish or drive them to deeper waters. Barometric pressure is another critical factor; stable or rising pressure often signals active feeding, while falling pressure (indicating an approaching storm) can make fish less active. Light conditions, such as dawn, dusk, and overcast days, often trigger feeding frenzies, as these times offer cover from predators. Additionally, local factors like tidal currents (especially in saltwater), bait availability, and the presence of cover (e.g., structure, vegetation) all play a crucial role. For instance, many predatory fish are most active during low light conditions, and a strong tidal current can concentrate baitfish, leading to prime feeding opportunities regardless of the solunar index.

Variations in Solunar Theory and Prediction Methods

While the core premise of solunar theory—that celestial bodies influence fish activity—remains consistent, various implementations and interpretations exist, leading to slight differences in predictions. Most solunar charts identify major periods around the moon's upper and lower transits (directly overhead or underfoot) and minor periods when the moon is rising or setting. However, the exact duration assigned to these periods (e.g., 1.5 hours vs. 2 hours for a major period) can vary. Some advanced solunar models also incorporate local tidal data more precisely, as lunar-solar gravitational forces are the primary drivers of tides, which in turn strongly influence fish behavior in coastal and estuarine environments. Furthermore, the weighting of factors like moon phase, season, and even specific species behavior can differ across various solunar prediction apps and guides, meaning an "Excellent" rating on one chart might be a "Good" on another, requiring anglers to find a system that resonates with their local experience.

Frequently Asked Questions

What is solunar theory in fishing?

Solunar theory in fishing suggests that fish and wildlife activity, particularly feeding, is influenced by the positions of the moon and sun relative to Earth. It posits that there are specific 'major' and 'minor' periods each day when activity is heightened, primarily around lunar transits (when the moon is directly overhead or underfoot) and anti-transits. This theory provides a framework for predicting peak activity times to improve fishing success, although its scientific backing is debated.

How do moon phases influence solunar fishing predictions?

Moon phases significantly influence solunar fishing predictions because they dictate the gravitational pull that affects tides and, consequently, fish behavior. New moons and full moons, where the sun, moon, and Earth are aligned, create the strongest gravitational forces, leading to the most pronounced tides and generally higher solunar activity. Quarter moons, with weaker tidal forces, are typically associated with reduced solunar influence, making these phases crucial for assessing potential peak activity.

What is a 'major' solunar period versus a 'minor' period?

A 'major' solunar period is a primary peak activity window, typically lasting about two hours, occurring when the moon is directly overhead (lunar transit) or directly underfoot (lunar anti-transit) at your fishing location, coinciding with high and low tides. 'Minor' periods, lasting about 45 minutes, occur roughly halfway between the major periods (i.e., when the moon is on the horizon, rising or setting). Major periods are generally considered to be the most productive fishing times due to stronger gravitational influences.