Best Water Temperatures for Rainbow Trout Fishing (Guide)

Water temperature is the most crucial thing to consider when setting off to fish for rainbow trout, and it can decide how you should approach your angling to net the most fish.

For rainbow trout fishing, water temperatures between 50°F and 60°F generally offer good fishing conditions, with the optimal range being around 55°F. This is when rainbow trout are actively feeding and more responsive to baits.

Water Temperature (°F)	Quality of Rainbow Trout Fishing
Below 40°	Slow activity, reduced feeding, sluggish movement.
41-50°	Gradually more active, feeding increases, moderate movement.
51-60°	Active feeding, more movement, willingness to chase lures.
61-68°	Peak activity, aggressive feeding, actively chasing lures.
69-73°	Sustained activity, feeding consistently, exploring shallower areas.
Above 74°	Activity decreases, seek cooler, deeper waters, feeding slows down.

While even seasoned fishermen might tell you that rainbow trout will bite at any temperature (which isn’t entirely wrong), there are certain things to consider in how differences in temperature and sudden shifts can change rainbow trout feeding habits.

This article will cover the ideal temperatures for rainbow trout fishing, emphasizing typical trout behavior at given temperature ranges, what baits and lures to use for different conditions, and how trout react to storms and sudden changes in water temperature.

Rainbow Trout Fishing by Water Temperature

Below 40°

Cold Water (Below 40°F / Below 4.5°C):

Rainbow trout become quite lethargic in very cold water and may move to the deepest parts of the stream.
Look for them in slow-moving pools where the water is warmer and more stable.
Their feeding slows down significantly, and they may focus on conserving energy.
Using larger nymph flies like stoneflies and streamers that mimic small fish can be effective during these conditions.
Techniques such as “dead drifting” or “slow stripping” can work well to entice bites.
Fishing during the warmest parts of the day when the water temperature may slightly rise can increase your chances.

41-50°

Chilly Water (41-50°F / 5-10°C):

Rainbow trout become more sluggish in cooler water and move to slower areas.
They seek shelter in deeper pools and runs where the water is more stable.
Focus on using small nymph flies that mimic aquatic insects like stoneflies and midges.
Techniques like “bottom bouncing” or “deep nymphing” can be effective.
Slow down your presentation and use lighter tippet to entice bites.
Fishing during the warmer parts of the day when the sun is out can increase your chances of success.

51-60°

Cool Water (51-60°F / 10.5-15.5°C):

Rainbow trout are quite active in this temperature range and move more to find food.
Look for them in riffles, runs, and deeper pools, as they seek oxygen-rich areas.
Rainbow trout focus on a variety of aquatic insects and small fish.
Using nymph flies that imitate these insects, like mayflies and caddisflies, can be effective.
Techniques such as “indicator nymphing” or “tight line nymphing” work well.
Early mornings and late afternoons are good times to fish when rainbow trout are actively feeding.

61-68°

Mild Water (61-68°F / 16-20°C):

Rainbow trout are quite active and feed more actively in this temperature range.
They move into shallow riffles, runs, and the edges of pools to find food.
Focus on using both nymphs and dry flies, as rainbow trout will target a variety of insects.
Look for hatches of mayflies, caddisflies, and stoneflies and match your fly to what’s present.
Techniques like “upstream nymphing” or “dry fly casting” work well.
Fishing during midday when insect activity is highest can lead to successful catches.

69-73°

Moderate Water (69-73°F / 20.5-22.5°C):

Rainbow trout are more active and energetic in this temperature range.
They move into riffles, runs, and shallower areas where there’s good oxygen.
They focus on a variety of food, such as aquatic insects, small fish, and crustaceans.
Use nymph flies that imitate these prey items and drift them naturally in the current.
Techniques like “dead drift” or “swing fishing” can attract bites.
Fishing during early mornings or late afternoons when the water is cooler can be more productive.

Above 74°

Warm Water (Above 74°F / 23.5°C):

Rainbow trout become more sluggish in warmer water.
They might seek cooler, oxygen-rich areas like deeper pools and shaded spots.
Focus on fishing during cooler times of the day, such as early mornings or late evenings.
They may feed less actively, but can still go after insects like caddisflies and mayflies.
Use lightweight dry flies that mimic these insects and present them delicately on the water’s surface.

Is Water Temperature a Big Factor in Rainbow Trout Fishing?

Rainbow trout are influenced by water temperature. When the water is cooler, around 50-60°F, rainbow trout tend to be more active and hungry. They swim closer to the surface and actively feed on insects, making dry flies and nymphs effective for catching them.

As the water warms above 60°F, rainbow trout may become less active and seek cooler, deeper areas. They might still feed but be more selective about their food.

Seasonal Water Temperature Guide for Rainbow Trout

Winter

Early Winter (Water Temperature: 30-40°F / -1-4.5°C):

Rainbow trout become more lethargic as water gets colder.
They move to slower pools and deeper areas where temperatures are more stable.
They focus on eating small insects and aquatic worms.
Use small nymph flies and present them near the bottom of the water.

Middle Winter (Water Temperature: 20-30°F / -6.5-1°C):

Rainbow trout are less active and conserve energy during the coldest months.
They seek out the warmest pockets of water and might stay close to the streambed.
Focus on using larger nymph flies and tiny midge patterns.
Techniques like “slow retrieve” or “deep drift” can attract bites.

Late Winter (Water Temperature: 30-40°F / -1-4.5°C):

Rainbow trout begin to stir as temperatures slowly rise.
They may move to slightly shallower waters.
Look for them in slower runs and deeper pools.
Continue using small nymph flies and consider adding a tiny split shot to get your fly deeper.

Remember, during winter, rainbow trout’s activity levels are lower, and they become more selective in their feeding.

Spring

Early Spring (Water Temperature: 45-55°F / 7-12.5°C):

Rainbow trout become more active as the water warms up.
They move to shallower areas like river edges and pools to find food.
Focus on using nymph flies that imitate insects like mayflies and stoneflies.
Techniques like “dead drifting” your fly along the current can attract bites.

Middle Spring (Water Temperature: 55-60°F / 12.5-15.5°C):

Rainbow trout become even more active and might start feeding on insects at the water’s surface.
Look for them in areas with gentle currents and eddies where insects collect.
Use dry flies that resemble emerging insects, like caddisflies or mayflies.
Techniques such as “matching the hatch” – using flies that mimic the insects hatching – can be effective.

Late Spring (Water Temperature: 60-65°F / 15.5-18.3°C):

Rainbow trout are feeding actively and moving to slower sections near banks.
They focus on insects like mayflies, caddisflies, and small fish.
Continue using dry flies, and try terrestrial patterns like grasshoppers or ants.
Techniques like “skating” the dry fly lightly on the water can attract their attention.

Summer

Early Summer (Water Temperature: 60-70°F / 15.5-21°C):

Rainbow trout remain active but may seek cooler, deeper waters as temperatures rise.
Look for them in shaded areas, under overhanging trees, or near structures.
They focus on insects like mayflies, caddisflies, and aquatic worms.
Use nymph flies that imitate these insects, and present them near the bottom of the water.

Middle Summer (Water Temperature: 70-75°F / 21-24°C):

Rainbow trout become more cautious as water temperatures increase.
They might move to deeper pools and runs where water is cooler and more oxygenated.
Focus on fishing during early mornings or late evenings when temperatures are cooler.
Continue using nymph flies or switch to streamers to imitate small fish.

Late Summer (Water Temperature: 75-80°F / 24-27°C):

Rainbow trout become less active and may become lethargic in warm water.
Look for them in areas with fast-moving, oxygen-rich water, such as riffles and runs.
They might focus on larger insects or even small fish.
Consider using larger streamer flies to provoke strikes.

Fall

Early Fall (Water Temperature: 60-70°F / 15.5-21°C):

Rainbow trout become more active as temperatures start to cool down.
They may move to shallower waters and areas with good oxygen levels.
Focus on using nymph flies that imitate insects like caddisflies and mayflies.
Techniques like “drift fishing” or “swing fishing” can attract bites.

Middle Fall (Water Temperature: 50-60°F / 10-15.5°C):

Rainbow trout become even more active as water cools further.
Look for them in runs and riffles where they can find abundant food.
They focus on insects like mayflies, caddisflies, and small fish.
Use dry flies and streamers to imitate these prey items.

Late Fall (Water Temperature: 40-50°F / 4.5-10°C):

Rainbow trout are at their most active as they prepare for winter.
They may move to deeper pools and runs to conserve energy.
Focus on using larger streamers that imitate larger prey like minnows or leeches.
Techniques like “dead drifting” or “stripping” the streamer can be effective.

Rainbow Trout Fly Fishing: Best Water Temps

Best Water Temperature: Nymphs

The best water temperature range for nymph fishing for rainbow trout can vary based on the season:

Spring: When the water temperature is between 50-55 degrees Fahrenheit (10-12.5 degrees Celsius), rainbow trout are often active and feeding, making it a good time for nymph fishing.
Summer: In the warmer months, when the water temperature is around 55-65 degrees Fahrenheit (12.5-18.3 degrees Celsius), nymph fishing can still be productive, especially in the early morning or late afternoon.
Fall: As temperatures start to cool down, around 50-55 degrees Fahrenheit (10-12.5 degrees Celsius), rainbow trout become more active again, making nymph fishing a viable option.
Winter: Nymph fishing can be effective in winter when the water temperature is around 40-45 degrees Fahrenheit (4.4-7.2 degrees Celsius), as rainbow trout remain active in slightly colder water.

Best Water Temperature: Streamers

The best water temperature range for streamer fishing for rainbow trout can vary depending on the season:

Spring: When the water temperature is between 45-55 degrees Fahrenheit (7-12.5 degrees Celsius), rainbow trout can be more active and aggressive, making streamer fishing effective.
Summer: In the warmer months, streamer fishing can work well when the water temperature is around 55-65 degrees Fahrenheit (12.5-18.3 degrees Celsius), especially during low light conditions or when trout are seeking deeper, cooler waters.
Fall: As temperatures cool down, around 45-55 degrees Fahrenheit (7-12.5 degrees Celsius), rainbow trout can become more active again, providing good opportunities for streamer fishing.
Winter: Streamer fishing can be productive in the winter months when the water temperature is around 40-45 degrees Fahrenheit (4.4-7.2 degrees Celsius), as rainbow trout continue to feed in slightly colder water.

Best Water Temperature: Dry Flies

The best water temperature range for dry fly fishing for rainbow trout can vary throughout the seasons:

Spring: When the water temperature is between 50-60 degrees Fahrenheit (10-15.5 degrees Celsius), rainbow trout become more active and are likely to rise to the surface to feed on insects, making dry fly fishing effective.
Summer: In warmer months, dry fly fishing is often productive when the water temperature is around 60-70 degrees Fahrenheit (15.5-21 degrees Celsius), especially during early mornings or late evenings.
Fall: As temperatures start to cool down, around 50-60 degrees Fahrenheit (10-15.5 degrees Celsius), rainbow trout may continue to feed on the surface, providing good opportunities for dry fly fishing.
Winter: Dry fly fishing can be less common in the colder months, but when the water temperature is around 45-50 degrees Fahrenheit (7-10 degrees Celsius), there might still be chances to see trout rising to take insects on the surface.

Does Air Temperature Impact Rainbow Trout Fishing?

Air temperature plays a significant role in rainbow trout fishing. Here’s how it impacts them:

Feeding Activity: Warmer air temperatures can increase the metabolism of rainbow trout, making them more active and more likely to feed. In cooler air, their activity might decrease.
Surface Activity: In warmer air, rainbow trout might rise to the water’s surface to feed on insects more frequently. Cooler air could lead to less surface feeding.
Preferred Locations: In warmer air, rainbow trout might move to shallower areas or near the water’s surface to find food. In cooler air, they could seek deeper, cooler spots in the water.
Insect Activity: Warmer air temperatures can lead to more insect hatches, attracting rainbow trout to the surface to feed.
Fishing Techniques: When the air is warmer, using dry flies that resemble insects on the water’s surface can be effective. In cooler air, nymphs and streamers imitating underwater food sources might work better.

It’s important to consider the air temperature when planning your fishing trip and adapt your tactics based on how the rainbow trout respond to the changing conditions.

How Cold is Too Cold for Rainbow Trout Fishing?

In the colder months of winter, when water temperatures drop below 40°F, rainbow trout can become less active and slow down their feeding. Extremely cold water, around 32°F or freezing, can cause ice to form on the surface, making fishing challenging and unsafe.

When it comes to air temperature, if it gets too cold, such as below freezing, it can lead to freezing water and ice formation, making fishing nearly impossible. Additionally, very cold air temperatures can affect your fishing comfort and safety.

Generally, for good rainbow trout fishing, you’ll want to aim for water temperatures above 40°F in the winter. Similarly, air temperatures above freezing are more comfortable and safer for fishing.

Click here to learn the best water temperature for trout.

How Hot is Too Hot for Rainbow Trout Fishing?

During spring, when the water temperature is around 45-55°F, rainbow trout are most active and readily feed. As summer arrives and water temperatures rise to 60-70°F, trout may become less active, seeking cooler, deeper waters to avoid stress.

When fall arrives and the water cools to around 50-60°F, rainbow trout become more active again, preparing for winter. In colder months, water temperatures below 40°F can slow down trout metabolism, making them less likely to bite.

When it comes to heat, if the air temperature gets too hot, such as over 80°F, it can warm the water and stress rainbow trout, causing them to become sluggish and seek deeper, cooler areas. Similarly, if the water temperature goes above 70-75°F, it can stress the fish, and they might stop feeding altogether to conserve energy.

Storms & Weather Changes: Impact on Rainbow Trout Fishing

Impact of Storms and Weather on Rainbow Trout Fishing:

Before a Storm: Rainbow trout can become more active and aggressive as a storm approaches, sensing changes in barometric pressure. They may feed more actively as they anticipate the pressure drop.
During a Storm: Fishing during a storm can be challenging and unsafe due to rough conditions. Trout may be less active and less likely to feed, seeking shelter in deeper areas.
After a Storm: After a storm, fishing can improve. The increased oxygen levels and cooler water temperature can stimulate feeding. Focus on using natural-colored flies and present them near the surface where trout may search for dislodged insects.
Cloudy Days: Overcast days can create ideal low-light conditions for rainbow trout to feel safer while feeding. Using streamers, nymphs, or wet flies can be effective during these times.
Sunny Days: Trout may retreat to deeper waters on sunny days to avoid direct sunlight. Nymph fishing in deeper pools or using dry flies in shaded areas can yield results.
Wind: Wind can create ripples on the water’s surface, making it harder for trout to detect predators. This can benefit fly fishermen, as trout may feel less wary about coming to the surface to feed.
Temperature Changes: Drastic temperature changes can affect trout behavior. On warmer days after a cold spell, they may become more active. On colder days following warmth, they might be less active.

Click here to see the best water temperature for trout. Click here to see how to catch trout on cloudy days. Click here to see how to catch trout on sunny days. Click here to see how to catch trout on windy days. Click here to see the best water temperature for brown trout. Click here to see the best water temperature for brook trout.