Best Time to Book

Seattle → Boston flights

Seattle to Boston fares hover around a $172 median with only a 9% spread, so there's little incentive to time your booking precisely.

SEA–BOS fares are steady near $172 — spread is tight

Key takeaways

Median fare is $172, with the full observed range just $169–$184
Spread of only 9% signals a stable fare environment — not much upside to timing tricks
Bottom quartile sits at $169, nearly identical to the low, suggesting prices rarely dip far below median
Top quartile is $184, so even the pricier end stays close to the median
Sample size of 12 snapshots is on the thinner side, so treat this as a directional read rather than a precise forecast

30-day price trend

SEA → BOS · cheapest cached fare per day · last 13 days · ↓ 1%

$169 low$184 high

See full numbers and stats on the SEA → BOS price history page.

The full picture

The data shows a notably tight fare band for Seattle to Boston: a $169–$184 range across 12 snapshots, with a median of $172. A 9% spread is low by airfare standards, which tells us this route doesn't swing wildly based on when you check — unlike routes where fares can double depending on timing. If you're budgeting for this trip, $172 is a reasonable number to plan around, and you're unlikely to find a dramatically better deal by waiting or a dramatically worse one by booking soon.

Because the spread is so narrow, we can't point to a clear window in the booking horizon where prices reliably soften — the data simply doesn't show enough volatility to identify one. The p25 ($169) and the low ($169) are essentially the same value, which reinforces that even the cheapest fares observed aren't meaningfully lower than the typical price. Similarly, the p75 ($184) is close to the high ($184), meaning the upper end of pricing is also well-contained. In practice, this means booking whenever it's convenient for your travel plans is a defensible strategy here, rather than holding out for a rare dip.

We don't have enough visibility into carrier mix or day-of-week patterns from this dataset to make claims about specific airlines or departure days — the data provided doesn't break fares out that way. One honest caveat: with only 12 snapshots, this is a thinner sample than we'd like for high-confidence conclusions, so treat the $172 median as a solid ballpark rather than a guaranteed price point, and expect some natural variation if you check fares yourself.

Ready to look at fares?

Search SEA → BOS on Aviasales →See the price history →

Related travel pages

Why we regenerated this article: Snapshot depth changed (5 → 12 samples). We only rewrite when the underlying price index actually moves — stable weeks keep the previous take.

AI-authored from this route's 30-day price index. Article last regenerated Oct 10, 2026. Fares shift continuously — confirm at booking.