Air Pressure and Fishing: High, Low and Falling Pressure

By Alex Clayton · Updated 23 October 2026

One UK carp guide rates anything under 1000mb as the best you can get. A US weather-station maker says steady, normal pressure is best, and quotes it in inches of mercury. So what is the best air pressure for fishing?

There is no single figure. Low or falling pressure, roughly below 1010mb, is the traditional sign to fish on the bottom. Under high pressure, 1020mb and up, carp writers say fish sit higher in the water and feed in shorter spells. The trend, and the weather that comes with it, matters more than the number.

The only angler-catch study we found, on a US lake, showed pressure change made almost no difference, so treat pressure as a weather signal, not a switch.

Below: reading the numbers, checking the trend and tactics for each pressure state, for carp, pike, perch and bream. It is part of how weather affects fishing.

Step 1: Learn What the Pressure Numbers Mean (mb, hPa and inHg)

Remember one number: 1013. That is roughly average sea-level pressure (the standard atmosphere is 1013.25 hPa), so anything above it is higher than average and anything below is lower.

Millibars (mb) and hectopascals (hPa) are the same unit. The Met Office surface pressure charts mark high and low centres in hPa, and the Met Office links high pressure with settled weather and low pressure with unsettled weather.

For carp, Angling Times treats below about 1010mb as low and 1020 to 1030mb as high.

Reading (mb)	What it usually means	Typical weather
Below 1000	Deep low	Wet and windy
1000 to 1010	Low	Unsettled, cloud and showers
1010 to 1020	Around average	Mixed
1020 to 1030	High	Settled, lighter wind
Above 1030	Strong high	Still, frost in winter, heat in summer

American guides use inches of mercury (inHg). One inHg is about 33.9mb, so 29.92 inHg is roughly 1013mb. Tempest’s “normal” band of 29.70 to 30.40 inHg converts to roughly 1006 to 1030mb (our rounded conversion).

If your app or barometer shows inches, multiply by about 34 to get mb.

Step 2: Set Your Expectations: What the Science Says About Fish and Pressure

A 30mb weather swing changes the pressure on a fish by about the same amount as swimming 30cm deeper. Rough arithmetic: one atmosphere is roughly a 10.3m column of fresh water, so 1mb is about 1cm. Dropping from 1m to 2m adds about 100mb, over three times that swing.

Fish do sense pressure. In a 2021 lab study, Davis and colleagues showed Mexican cavefish learning to use water pressure as a depth cue. The mechanism is unknown (the swim bladder is a candidate) and weather pressure was not tested.

Shaw, Renik and Sass (2021) analysed 13 years of angler records from Escanaba Lake, Wisconsin. Daily change in barometric pressure did not significantly predict walleye or muskellunge catches. Lunar position and angler factors mattered more (see moon phases and fishing), but these are American species.

We found no peer-reviewed study on carp, pike, perch or bream and barometric pressure, so UK advice on barometric pressure fishing is experience, not proof. Angling Times claims oxygen peaks at low pressure but gives no evidence, so treat it as unproven.

What pressure does forecast is wind, cloud, rain and temperature. Gaz Fareham of CARPology says he cannot be sure whether carp react to the pressure or to the weather that arrives with it.

Treat pressure as a forecast of conditions, not a bite switch.

Step 3: Check the Pressure Trend Before You Go

Your phone says 1015mb and you still don’t know whether to go. Which way it is moving tells you far more than the figure.

Look back 24 hours and ahead 48. Use a barometer, a weather app or the Met Office surface pressure chart, which forecasts several days ahead for free.
Find your area on the chart. Note whether you are inside an L, close to a front or under an H.
Check the isobar spacing. The Met Office explains that closely packed isobars mean a steeper pressure change over a short distance, so stronger wind. Wide spacing means light wind.
Classify the day as falling, rising or steady. As a rule of thumb, a drop of several mb over a day counts as falling.
Note wind direction, cloud and air temperature alongside. As Step 2 explained, these may be doing most of the work.

Our fishing tools and forecasts pull these readings together in one place.

By now you should know whether your session falls under low and falling, high and steady, or changing pressure. That sets your tactics in Steps 4 and 5.

Best for: planning a session a day or two out. Skip if: you are already on the bank and the fish are feeding.

Step 4: Fishing Low Pressure: Fish the Bottom and Bait More Positively

Barometer dropping, wind getting up? Most UK carp writers say put your bait on the deck and don’t be shy with it:

Angling Times says carp tend to feed on the bottom when pressure is low.
Gaz Fareham (CARPology) goes heavier with bait and fishes spots with a little more depth, saying carp seem to feed harder and for longer.
DNA Baits rates falling or stable pressure with a rising south-westerly and low light as prime conditions.
Angling Times also flags summer and autumn, when a low arrives after a spell of high pressure with a big southerly or westerly wind.

More on wind and temperature in our carp fishing weather guide.

For bream and roach, a feeder fished on the bottom with a steady trickle of bait suits these overcast, breezy days. For pike and perch, coloured, choppy water and low light suit bigger lures and static deadbaits. On Windermere, when it turns rough and grey, I tend to reach for the feeder for bream or a static deadbait for pike.

Lows can bring thunder, so pack up if lightning is close: carbon rods conduct electricity.

If the pressure is falling into the weekend, start on the bottom with more bait than usual.

Step 5: Fishing High Pressure: Go Higher, Lighter and Earlier

The only day you can go is under a big high: flat calm, bright sun, maybe a frost. As Angling Times points out, sitting at home cursing the weather catches nothing.

Angling Times says carp are often more lethargic and higher in the water. Fish zig rigs or off the surface rather than spodding bottom baits, and try shallow, sheltered areas and margins.
Gaz Fareham uses zigs in winter and floaters in summer once the first-light feeding spell has passed.
Bait lightly. A small scattering or a single hookbait is the common approach, not a big bed.

In clear, bright water, fish often hold tight to cover, depth or shade. Scale down for roach on the float, with a size 16 to 18 hook as a general guide, and slow everything down for perch. On settled, bright days on Windermere I usually fish a drop-shot rig slowly for perch, or keep to float tactics close to cover.

Under bright high pressure, first and last light are your best windows. See the best time of day to go fishing.

Compared with Step 4: low pressure means the bottom, more bait and longer feeding spells; high pressure means up in the water, less bait and short windows.

Step 6: Match Your Tactics to Pressure and Season, Then Keep Your Own Record

If respected sources can’t agree on the best pressure for carp fishing, whose number do you trust? Yours. Angling Times rates below 1000mb best and 1010 to 1020mb moderate, DNA Baits favours falling or stable pressure, and Tempest (US) prefers steady, normal pressure. All are rules of thumb.

Pressure state	Usual weather	Where to fish	Bait and method	Season notes
Low or falling	Wind, cloud, rain	Bottom, deeper spots	Feeder or bottom baits, more bait	Angling Times rates summer and autumn lows after a high
Steady, 1010 to 1020mb	Mixed	Normal swims	Your usual approach	Follow wind and temperature
High, summer	Bright, warm	Up in the water, margins	Zigs, floaters, light baiting	Fish early and late
High, winter	Cold, clear, frost	Up in the water, sheltered spots	Zigs, small baits, fished slowly	Angling Times suggests settled spells with rising temperature or pressure

Note pressure, trend, wind, cloud and air temperature each session, then look back after a season. Your own water beats any magazine band.

Frequently asked questions

What is the best air pressure for carp fishing?

There is no agreed figure. UK carp writers lean towards low or falling pressure, under about 1010mb, for bottom fishing, and treat 1020mb and above as zig and surface conditions. Angling Times and DNA Baits disagree on the exact bands, so use them as rough guides. See Step 6 for the full table.

Is falling pressure good for fishing?

Many anglers rate the spell as pressure drops ahead of a front, with wind and cloud building; DNA Baits and Tempest both mention it. The evidence is anecdotal. The one large catch study we found, Shaw and colleagues in 2021 on walleye and muskellunge in Wisconsin, showed pressure change made almost no difference.

Can you catch fish in high pressure?

Yes. Fish higher in the water or in sheltered margins, bait lightly and target first and last light, the usual best windows on bright days. Zigs and floaters work for carp, while finer tackle and a slower approach suit roach and perch. See Step 5 for the full approach.

Do fish feel changes in air pressure?

Fish can sense water pressure, as a 2021 lab study by Davis and colleagues showed. But a 30mb weather change is about the same as moving roughly 30cm deeper, which fish do constantly. The wind, cloud and temperature that come with pressure changes probably matter more.