Flight time & jet lag: London to New York

London to New York: Route overview

This westbound transatlantic route covers 5,540 km from London to New York, crossing the Atlantic with prevailing westerly headwinds that typically extend the 6h 39m to 7h 35m journey by 20–40 minutes compared to the eastbound return. The 5-hour westbound shift means your body clock will be noticeably out of sync for 2–3 days, affecting sleep quality, appetite, and concentration at your destination. Both cities sit at similar temperate latitudes, meaning daylight patterns will feel familiar upon arrival — a helpful factor for circadian adjustment.

What makes the London–New York route different

While westbound travel is generally easier than eastbound (your day gets longer rather than shorter), crossing 5 time zones still creates substantial disruption. The advantage is that most people find it easier to stay awake past their usual bedtime than to fall asleep earlier.

Arrival strategy for New York

Flying west to New York gains you 5 hours, extending your arrival day. At 18:00 local time, your body will think it is 23:00 — meaning you will feel ready for sleep well before the local bedtime. Counter this by getting bright light in the late afternoon and early evening. Eat dinner at the local time, stay physically active, and push your bedtime to at least 21:00 local. Avoid morning light before 08:00 on the first few days, as this would advance your clock in the wrong direction.

Circadian rhythm analysis: London → New York

When you arrive in New York, your circadian rhythm is still running on London time. At 09:00 New York time, your body reads 14:00 — your body's mid-afternoon, meaning you will be alert and functional during the local morning. The main westbound challenge is that by 22:00 local, your body clock reads 03:00 — the deep night on your internal clock. You will feel intensely sleepy well before the local bedtime. Your circadian system adjusts at roughly 1 to 1.5 hours per day, so expect 4 days for full alignment.

Your body clock in New York (day 1)

How your body clock maps to local time upon arrival, before any adjustment.

Pre-departure preparation

For this 5-hour westward shift to New York, start 4 days before departure by delaying your bedtime by 75 minutes each night. Seek bright light in the evening hours to help push your clock later. On the flight, try to stay awake if arriving during New York's daytime. This gradual shift can significantly ease your transition upon arrival.

Your first 72 hours in New York

Day 1 in New York: Your body is ~5 hours off local time. Stay active and seek afternoon sunlight. Push bedtime to at least 21:00 local. Eat at local mealtimes even if not hungry. Caffeine is fine before 16:00, not after. Day 2: ~4 hours off. Continue late afternoon (15:00–18:00) light exposure. Sleep quality should improve. Day 3: ~2 hours off. Noticeable improvement. Maintain light and meal timing discipline.

Recovery timeline

Full circadian adjustment for the London → New York route typically takes 4 days, based on the body's natural adaptation rate of ~1 to 1.5 hours per day for westbound travel. During this period, expect gradually improving sleep quality, with the most noticeable symptoms (fatigue, difficulty concentrating, appetite changes) during the first 3 days. By day 4, most travelers report feeling fully synchronized with New York's schedule.

Route Planner

Adjust departure date for DST-accurate results.

Jet lag adjustment plan: London → New York

Noticeable fatigue and sleep disruption for 2–3 days. Plan for adjustment.

Business hours: London vs New York

Seasonal and climate factors

Transatlantic flight times between London and New York vary seasonally: winter jet streams can reduce eastbound flights by 30–45 minutes while extending westbound flights by a similar amount. Summer typically sees more moderate wind patterns. New York at 41°N experiences moderate seasonal daylight variation. Summer offers longer evenings useful for westward adjustment, while winter's earlier sunsets support eastward adjustment schedules.

How the London–New York flight time is estimated

The 6h 39m to 7h 35m estimate for London to New York is derived from the 5,540-km great-circle distance. Long-haul flights spend most of their duration at optimal cruise altitude (typically 35,000–40,000 feet), achieving effective speeds of 820–900 km/h. An additional 30–50 minutes accounts for taxi, takeoff, climb, descent, approach, and taxi at both LHR and JFK. This oceanic route means actual flight paths follow organized track systems that may deviate from the great-circle distance, potentially adding 5–10% to the theoretical minimum path. Prevailing winds along this corridor can shift the actual time by 20–60 minutes in either direction.

Wind patterns and flight duration

Westbound flights from London to New York fly against the North Atlantic jet stream, adding time compared to the eastbound leg. Airlines often route these flights on more southerly tracks to minimize headwind exposure, which increases the path distance but can still reduce total time.

Practical travel context

As a transatlantic connection between London and New York, this route is primarily served by full-service carriers with seasonal charter supplements. Direct flights typically use wide-body aircraft suited to the 5,540-km distance. Most travelers on stays of 3 days or longer will benefit from fully adjusting to New York's local time, as the 5-hour shift is manageable within the first 2–3 days with proper light and sleep management.

Frequently asked questions: London to New York

More questions about this route

Related routes