Barometric pressure, also referred to as atmospheric pressure, is the pressure inside of the earth’s atmospheric. More specifically, this is the weight of the air pressing down at any given point on the planet and the pressure is measured with a barometer.
But have you heard that barometric pressure can actually affect fishing and hunting?
How Barometric Pressure Works
Barometric pressure is measured in inches of mercury on a mercury barometer. These measurements are taken in millibars at a specific location and knowing the exact pressure reading in millibars can help determine weather changes. The normal atmospheric pressure at sea level reads 1013 millibars, or 30 inches of mercury.
Television weather personalities always talk about high- and low-pressure systems moving through an area. Here they are referring to the change in the barometric pressure rising or falling. High pressure systems, or when the barometric pressure is high, keeps the weather more stable as the higher pressure keeps bad weather, or low pressure systems at bay. During periods of high barometric pressure the cloud cover and humidity are lower, whereas the reverse is true in a low-pressure system and precipitation is much more likely. One reason for this is because the colder air rises faster than warmer air and results in more moisture being sent into the atmosphere.
The barometric measurement, or reading, changes due to temperature fluctuations and the altitude the reading is taken at. The atmospheric pressure is always lower at higher elevations because there are fewer molecules pushing down on the air at 10,000 feet then there are at sea level. By being able to understand why the changes in barometric pressure occur, and what those changes mean for weather patterns, you can anticipate how it may affect hunting conditions.
Does Barometric Pressure REALLY Affect Hunting?
Studies have shown that animals are highly sensitive to changes in weather patterns and it is believed this is one reason animals tend to move more just before a storm front moves in and after right it moves out. Even though barometric pressure is crucial element in determining the movement of game, it can be difficult to evaluate without some types of specialized equipment.
While hunters are quick to notice macro changes in weather patterns, such as snow, rain and wind, knowing the changes in barometric pressure that indicates these changes are on the way can be much more valuable to hunting success.
There are numerous studies that have shown that an animal’s sense of smell is better at during periods of high barometric pressure. This is due to scent rising more when the air molecule are warmer. This seems to be borne out by varmint hunters reporting that coyotes seem to pick up their sent at greater distances in times of high pressure. Here it is worthy to note that deer have a slightly better sense of smell than canines as they have slightly more olfactory sensors.
Deer tend to behave similarly to people when a weather front is moving in. This is why one of the best times to hunt is when the barometric pressure is starting to fall, signaling an impending storm moving in. Because they are able to sense this impending change in the weather, deer begin to feed more aggressively in order to prepare for being able to wait out the storm for hours or even days.
Specifically for Deer, What Is the Best Barometric Pressure?
While some people say that changing barometric pressure is of little to no consequence for deer hunting, there is a good deal of data that should at least have you questioning the naysayers.
The inner ear of a deer works similarly to a barometer and allows them to sense major changes in atmospheric pressure. Data and personal accounts from Mossy Oak Gamekeepers indicates the greatest increase in deer activity tends to occur with a rapid drop in pressure of four- to five-tenths of an inch.
As standard atmospheric pressure readings vary greatly from one region to the next, there is no “best” barometric pressure reading. Knowing exactly when the barometric pressure will start to fall will greatly benefit you as a hunter to know the weather is going to change before the deer do, allowing you to get into the field sooner, ahead of the beginning of the storm, when deer activity will be at the highest. Knowing when the barometric pressure will change may be even more important for trophy hunters as these are the times when those elusive mature bucks will be on the move during daylight hours.
For example, once the pressure starts to fall the storm has already started moving in and deer may have already finished there pre-storm feeding activity and moved to a secure bedding area to wait it out. This why one of the best times to hunt is when the barometric pressure just begins to fall.
Keith McCafferty, contributing writer for Field and Stream, reported that wildlife biologists in North Carolina trapped 68 whitetails in four nights with a falling barometer, whereas only 65 deer were caught over a 10-week period when the pressure was stable.
However, data has shown that deer move more after holding up for a protracted period. This means that once the storm is over, and the barometric pressure starts to rise, deer activity tends to skyrocket.
Again, knowing when the barometric pressure will be changing ahead of when the deer do, will again allow you to get the jump on their feeding behavior. However, while it should be taken into account when planning your hunt, it is important to understand that barometric pressure is but just one factor that contributes to wildlife movement patterns.
2 Barometric Pressure Hunting Apps that Might Be Useful:
While barometric pressure can be obtained with a barometer, walking around with one in your pocket may not be all that practical. Luckily there are more convenient and efficient ways of knowing when the weather is gong to change.
There is no shortage of smartphone apps that can help you plan your hunt. However, not all weather apps are created equally. The best weather apps for hunting are those that not only give you the barometric pressure, but also tell you when the weather is expected to change, how much precipitation is expected, wind speed and direction and how long a storm is expected to last. Some even have real-time weather radar maps that show when areas of high and low pressure are expected to pass through your hunting area. Here are the two best:
1. The Weather Channel App
While not designed specifically for hunters, this free app comes from The Weather Channel, one of the most respected names in weather reporting, This app has all the weather data you could possible need for timing your hunt:
• Hourly, daily, 10- and 30 day weather forecasts.
• Live weather reports.
• Temperature and precipitation along with wind speed and direction readings.
• Predictions broken down by the hour for up to 30 hours.
• Current Barometric pressure reading and predictions.
• Sunrise and sunset times.
• Weather-radar maps that show you storm front movement in real time.
2. onX Hunt Wind & Weather
This is a paid app designed by hunters for hunters. This app uses Weather Underground stations for up-to-date weather reporting. While not as comprehensive as The Weather Channel App, onX it is a little more convenient as all of the info is in one place. Features include:
• Live weather reports.
• Current and long range weather forecasts.
• Temperature and precipitation predictions.
• Wind speed and direction.
• Sunrise and sunset times.
• Barometric pressure.
• Free trial.
Ready to Get Into Some Deer?
Unless you are a master tracker, deer hunting is all about catching the deer when they are on the move, and this typically means when they are moving between their feeding and bedding areas. As feeding activity also increases just before and immediately after a storm, knowing when that storm is passing through your area is key to being in the field at the right time.
While science has not yet been able to determine the best barometric pressure for deer hunting, data suggests that the more the barometric pressure rises the better the hunting will be. It is important to note that barometric pressure tends to rise the most after a low-pressure system, or storm, moves out of an area. Still, it is the major fluctuations in pressure that are more important as these indicate the beginning or end to a storm that will have the deer moving. Hitting it just right or missing it by just an hour can mean the difference between a filled tag and going home empty handed.