More than any other snowbird question—this is always at the top of the list. I’ll try to simplify. But if you know anything about the U.S. rule-making process, you know that simplification isn’t easy.
The basic rule of thumb is, as a visitor (snowbird), you must spend more time in your home country than in the United states. That breaks down to six months—not necessarily consecutively. You can do that in the aggregate (four, five, six, etc. shorter trips in the year) or one six-month marathon. If you choose the marathon, it doesn’t have to fit within one calendar year: example, leave October 15, 2010, plan on leaving the country by April 15, 2010. That’s permissible. If you miss by a couple of days, nobody is going to handcuff you at the border and cart you off to Guantanamo.
Also, if you are in the U.S. for the full-six month season, it’s ok if you fly home for 10 days or so to spend Christmas with your family and then return to the sun. There is no mandatory 10 or 30-day “exit” period before you can return. (Ross Quigley, president of Medipac International, which provides travel insurance to members of the Canadian Snowbird Association, tells me that if you do return home for that 10 days, it will be counted as part of your six-month quota if a border agent is sharp enough to catch it. But if you interrupt your winter trip in U.S. for 30 or more days, you will be given credit for two separate trips and the 30 days will not be calculated into your six month quote. Got it?) But don’t assume that after having spent six months in the U.S, you can return home for a day and head back south for another six months. You can’t do that, and if you try, you may be banned from entry—for a long time.
Americans like to have Canadian visitors. It’s good for business and border agents are not going to hassle you unless they suspect you are taking advantage of the rules and actually living in the U.S. without permission. If they suspect you are likely to disappear into the illegal immigrant underground, or are unable to support yourself while visiting, or don’t intend to return to Canada, or don’t have a “closer connection” to Canada than to the U.S., they have a lot of latitude is asking you to prove your Canadian residency status and making an instant judgment about your “temporary visitor” status. If they’re not satisfied your intentions are legitimate, they can turn you back and there’s not much you can do about it then and there. The last thing you want to do is argue about your legal right to enter their country. (Snowbirds who spend substantial periods of time in the U.S. each year should file IRS form 8840 with the IRS, which establishes whether or not you are required to file U.S. tax returns. You likely will not, unless you spend more than half a year in the U.S. But it proves your “closer connection” to Canada and is a good thing to have in your hip pocket. Any cross-border tax consultant will have the form or you can contact the Canadian Snowbird Association. They can provide one or tell you where you can get one. It’s no big hassle.)
Understand that the U.S. applies different, more liberal, rules for Canadian visitors than it does for visitors from other countries. So unless you are a habitual “overstayer” and your overstays have been recorded (which they not always are), you should have no problems.
If, however, you are doing business in the U.S., or working without permission, or otherwise generating income from your efforts, then the U.S. government wants to know about it and so does the taxman. In that case you need to get appropriate advice from professional tax consultants who specialize in cross border issues. (You can click on the International Tax Consult link on our homepage for one such reference).
About the 182 days that seems fixed in so many Canadian minds: there is nothing in the U.S. immigration rules (which are so contorted you couldn’t possibly find simple explanations online or anywhere else) that specify 182-day limits. They do refer to six months, and by that they refer to month/days. That is: if you enter the U.S. on the 15th of any month for a continuous stay—be prepared to be out of the country on the 15th day of the sixth month after that.
The 182 days refers to the number of days most provinces require you to physically reside in your province in order to be considered a bona fide resident, eligible for provincial medicare. In Ontario, that threshold is 212 days. But that is a provincial rule and has no relationship or bearing on U.S. immigration rules. They just happen to coincide—nothing more.
Also, be aware that border agents in one part of the country (Vermont) don’t always talk to their colleagues in Montana, so you may find different ways of implementing the rules. Be reasonable, use common sense, always carry your passport (the best proof of permanent residency and legitimacy), and don’t get greedy. Remember, you are a visitor in someone else’s house.