In terms of precipitation, rainfall in Islip, New York ranges from 3.3 - 4.4 inches per month. March is typically the wettest month, when rainfall can reach 4.4 in. February is typically the driest time to visit Islip, New York when rainfall is around 3.3 in.

If weather is an important factor for your trip to Islip, New York, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 73.4 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 30.2 F).

How far in advance should I book a flight from Seattle to Islip, New York?

When searching for a good deal, it’s best to be prepared for potential fluctuations in price. We recommend booking at least 61 days in advance, which can save you up to 109% on flights from Seattle to Islip, New York compared to booking the week you need them. Waiting 61 days out may not be for everyone, so we have options available for flights within the next two weeks, with the lowest price starting at $412. For sooner than that we have options available in the next 3 days from $686.

What is the cheapest month to fly from Seattle to Islip, New York?

January is one of the best times of the year to fly to Islip, New York from Seattle. Prices for January average $393 per person but you can even find prices for as low as $230. The most expensive prices can be found in the month of December. Opting for a January flight can save you 28% on your journey compared to booking in December

What is the cheapest time of day to fly from SEA to ISP?

When flying from Seattle to Islip, New York, the time of day you decide to fly out makes little to no difference towards the overall price you’ll pay on tickets.

Can I find deals for flights from Seattle to Islip that include hotel bookings?

Yes. In addition to deals on Seattle to Islip flights, Cheapflights offers vacation packages that include both flights and hotel.

How can I find direct flights from Seattle to Islip?

After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Seattle to Islip.

Can I find deals for business class flights from Seattle to Islip?

Yes. Cheapflights offers flight deals from Seattle to Islip by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

$351+ Flights from Seattle to Islip, NY

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Cheap flight deals from Seattle to Islip

Round-trip from	$351 (Southwest)
Popular in	December
Cheapest in	January
Average price	$447

From Seattle/Tacoma Intl to Islip Long Island

Search Deals

Highest demand for flights based on searches. 2% potential increase in price ($9 potential increase over avg. RT price).

Search Deals

Cheapest flight prices on average. 2% potential price decrease ($11 potential savings vs. average RT price).

Search Deals

Average for round-trip flights in July 2025

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Find flight deals from Seattle to Islip

Cheapest flights from Seattle to Islip
Explore the most affordable flight options available from Seattle to Islip. Find the lowest fares from popular airlines and budget airlines, with prices last updated on July 29, 2025.

Wed 9/176:15 amSEA - ISP

2 stops12h 50mSouthwest

Sat 9/203:40 pmISP - SEA

1 stop7h 50mSouthwest

Deal found 7/28

$351

Best flights from Seattle to Islip
Discover carefully curated flight deals from Seattle to Islip that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated July 29, 2025.

Wed 9/179:10 pmSEA - ISP

1 stop11h 50mSouthwest

Sat 9/203:40 pmISP - SEA

1 stop7h 50mSouthwest

Deal found 7/28

$351

Fly from

Fly to

Route

Depart

Return

Price

SeattleIslip

SEA - ISP

SEAISP

Seattle/Tacoma Intl

Wed 9/17

9:10 pm-12:00 pm

1 stop11h 50m

Islip Long Island

Sat 9/20

3:40 pm-8:30 pm

1 stop7h 50m

$351

Flights are sorted by cheapest round-trip flights first.

Deals found on 7/28

Best time to book a flight from Seattle to Islip

Have a flexible travel schedule? Discover the best time to fly to Islip from Seattle with our price prediction graph.

Estimated round-trip price

Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.

Cheapflights Insights

Everything you need to know about your flight from Seattle to Islip

What is the cheapest month to book a flight from Seattle to Islip, New York?

Currently, January is the cheapest month in which you can book a flight from Seattle to Islip, New York (average of $108). Flying from Seattle to Islip, New York in November is currently the most expensive (average of $213). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

Reviews of airlines servicing Islip

See what other customers who have flown with Southwest from Seattle to Islip have to say. You can also see how each airline compares in terms of entertainment options, comfort, food, crew/service, and boarding process.

Southwest

8.0

Very good

4,238 reviews

Reviews

1 / 20

8.0

Excellent

Gina,Jul 2025

LAS - DEN

We experienced bad weather, which turned our 1.5 hour flight from Las Vegas to Denver, into 3.5. The pilot and crew kept us updated and explained that we had to circle and or possibly redirect to another airport. After circling for sometime, we were able to land smoothly in Denver. Thank you to all the flight crew, tower control, and all who got us to our destination safely.

Southwest

8.0

Very good

4,238 reviews

Southwest

8.0

Very good

4,238 reviews

Reviews

1 / 20

8.0

Excellent

Gina,Jul 2025

LAS - DEN

Related info for your journey

Can I find deals for flights from Seattle to Islip that include hotel bookings?
Yes. In addition to deals on Seattle to Islip flights, Cheapflights offers vacation packages that include both flights and hotel.
How can I find direct flights from Seattle to Islip?
After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Seattle to Islip.
Can I find deals for business class flights from Seattle to Islip?
Yes. Cheapflights offers flight deals from Seattle to Islip by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.
What is the cheapest month to book a flight from Seattle to Islip, New York?
Currently, January is the cheapest month in which you can book a flight from Seattle to Islip, New York (average of $108). Flying from Seattle to Islip, New York in November is currently the most expensive (average of $213). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

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Complete your trip

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$351+ Cheap flights from Seattle to Islip, NY (SEA - ISP)

This is the cheapest round-trip flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 9/17. Fares are subject to change and may not be available on all flights or dates of travel.

Find cheap flights from Seattle to Islip with Cheapflights

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2. Select your favorite providers

3. Compare prices and book

Cheap flight deals from Seattle to Islip

Round-trip from

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Cheapest in

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Find flight deals from Seattle to Islip

Cheapest flights from Seattle to IslipExplore the most affordable flight options available from Seattle to Islip. Find the lowest fares from popular airlines and budget airlines, with prices last updated on July 29, 2025.

Explore the most affordable flight options available from Seattle to Islip. Find the lowest fares from popular airlines and budget airlines, with prices last updated on July 29, 2025.

Cheapflights Fare Finder

Use the filters below to find and compare flights from Seattle to Islip that are best for you.

Best time to book a flight from Seattle to Islip

Have a flexible travel schedule? Discover the best time to fly to Islip from Seattle with our price prediction graph.

Cheapflights Insights

Everything you need to know about your flight from Seattle to Islip

What is the cheapest month to book a flight from Seattle to Islip, New York?

Reviews of airlines servicing Islip

Get insights into the airlines that provide service to Islip. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to Islip. Reviews last updated July 29, 2025.

See what other customers who have flown with Southwest from Seattle to Islip have to say. You can also see how each airline compares in terms of entertainment options, comfort, food, crew/service, and boarding process.

Related info for your journey

Find useful and relevant information for your journey from Seattle to Islip. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

Can I find deals for flights from Seattle to Islip that include hotel bookings?

How can I find direct flights from Seattle to Islip?

Can I find deals for business class flights from Seattle to Islip?

What is the cheapest month to book a flight from Seattle to Islip, New York?

Traveling to a place near Islip?

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Alternative routes for Seattle to Islip

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Cheapest flights from Seattle to Islip
Explore the most affordable flight options available from Seattle to Islip. Find the lowest fares from popular airlines and budget airlines, with prices last updated on July 29, 2025.