The 183-day rule is the most-cited and most-misunderstood number in snowbird planning. What it actually triggers, when it triggers, and how it interacts with Canadian banking and reporting obligations matters because the wrong assumption can turn a relaxed winter into a US tax return. This page summarizes the rule as it stands in 2026, what it does and doesn't do, and how it should shape banking choices. This is informational only — if you're close to any threshold, hire a cross-border accountant.

What the 183 actually is

The IRS substantial-presence test, not a single hard line. The test counts your physical presence in the US over a 3-year window using a weighted formula:

If the weighted total is 183 or more, and you spent at least 31 days in the US in the current year, you are presumed a US tax resident for the year. This is what most people mean by "the 183-day rule" — but the calendar-year 183 days is just one of several tripwires, not the only one.

The Closer Connection Exception

Even if you meet the substantial-presence test, you can typically avoid being treated as a US tax resident if you file Form 8840 (Closer Connection Exception Statement for Aliens) and:

Most snowbirds rely on Form 8840 every year. It is a relatively simple form but it must be filed by the US tax filing deadline (April 15, or June 15 with extension). Missing it can convert a routine winter into a US tax filing obligation covering worldwide income.

The Canada-US tax treaty tiebreaker

If both Form 8840 fails and you're caught as a US tax resident, the Canada-US tax treaty has tiebreaker rules (permanent home, center of vital interests, habitual abode, citizenship) that usually keep a typical Canadian snowbird's tax residency in Canada. But invoking the treaty requires filing US Form 1040-NR with a treaty position statement — much more involved than Form 8840 alone.

How this shapes banking choices

  1. FBAR doesn't apply to you (probably). FinCEN's Foreign Bank Account Reporting only applies to US persons (citizens, green card holders, tax residents). As long as Form 8840 keeps you a non-resident, your Canadian bank accounts don't trigger FBAR. Keep filing 8840.
  2. FATCA reporting by Canadian banks. If you tell a Canadian bank you have a US tax ID (SSN/ITIN) — which you likely do if you have any US property or income — the bank will report your account information to the CRA, which forwards to the IRS under the intergovernmental FATCA agreement. This isn't a tax obligation by itself; it's an information-sharing pipeline. Be aware that "the IRS has visibility" doesn't mean "you owe US tax."
  3. Don't put your "permanent" assets in US accounts. Closer Connection arguments rest on factors including where your primary bank is. Keeping your primary chequing, investment accounts, and emergency fund in Canada strengthens the case. Use US accounts for US-side operational needs (US bills, US debit card) but not as your primary financial life.
  4. Driver's license, voter registration, health card. These are explicit Form 8840 factors. Keep your Canadian credentials current. If you spend nine months in Florida and switch to a Florida driver's license, you've handed the IRS an argument.
  5. Provincial health coverage thresholds. Separate issue from US tax: provincial health insurance (RAMQ in Quebec, OHIP in Ontario, etc.) has its own day-count rules for maintaining coverage, usually requiring 183+ days/year in-province with some exceptions. Losing provincial coverage while abroad is a different and arguably bigger problem than US tax — verify your province's rules.

The day count nobody emphasizes enough

Days of entry and departure both count as US days under the substantial-presence formula, even partial days. A snowbird who flies into Florida on a Friday afternoon and out on a Sunday morning has counted three days, not two. Over a 4–6 month winter, this adds up. Keep a written log.

Bottom line

The framework: stay under 183 calendar-year days; file Form 8840 every year you spend more than 30 days in the US; keep banking and identity infrastructure clearly anchored in Canada; consult a cross-border accountant if any number gets close. Banking choices that align with this — primary accounts in Canada, US accounts for US-side operations only — protect the framework rather than complicate it.

Related reading

FAQ

If you stay under 183 days in the current calendar year and file Form 8840 every year, you can typically spend up to about 121 days/year averaged over three years without crossing the substantial-presence threshold. Even at higher day counts within the 121–182 range, Form 8840 usually resolves the issue if your ties to Canada are clear.
Yes — both the arrival day and the departure day count as US days for substantial-presence purposes, even partial days. This matters because four short trips of 5 days each (20 actual days on the ground) might count as 20 days, but a 5-month stay arriving Nov 1 and departing March 31 is roughly 151 days, not 150.
FBAR is a US tax obligation that applies to US persons (citizens, green card holders, US tax residents). A Canadian snowbird who stays a non-resident under Form 8840 generally doesn't have an FBAR obligation. Once you're treated as a US person (failed substantial-presence, no closer connection), the obligation kicks in for accounts outside the US, including your Canadian accounts.
Yes, it weighs against you on Form 8840's closer-connection factors. Keeping a Canadian driver's license is one of the cleaner pieces of evidence that your life is centered in Canada. Same logic for health card, voter registration, primary residence ownership.
If you meet substantial-presence and don't file 8840, the IRS can treat you as a US tax resident for that year, triggering a US tax return on worldwide income (with foreign tax credit for Canadian tax paid). You can sometimes file Form 8840 late with a reasonable-cause statement, but you're at the discretion of the IRS. A cross-border accountant can sometimes invoke the treaty tiebreaker on Form 1040-NR as a backstop.