Acording to the Bank of Canada, they fluctuate not only daily, but throughout the day as well depending on trades during time periods of the day. For instance, below is for the 23 and 24th:

Date     23/01/06        24/01/06
Can/US    1.1493          1.1525
closing
Can/US    1.1512          1.1549
noon
US/Can     .8687           .8659
noon

Notes:
*Rates are expressed in Canadian dollars, converted from U.S. dollars
*The noon exchange rate for the Canadian dollar against the U.S. dollar is calculated to reflect the trades that take place between 11:59 a.m. and 12:01 p.m. All other Canadian dollar noon exchange rates are derived from the US$/Can$ exchange rate and from indicative wholesale market quotes for a broad array of other currencies. Although obtained from sources believed to be reliable, the data are for informational purposes only, and the Bank of Canada does not guarantee their accuracy or completeness.

Is the webservice you referenced using an official, information, or reference rate instead perhaps? Those rates are published once a day.


>I just discovered something weird with the following Web Service:
>
>http://www.xmethods.net/sd/CurrencyExchangeService.wsdl
>
>Basically, it should be simple:
>
>

>loExchangeRate=Createobject("mssoap.soapclient30")
>loExchangeRate.mssoapinit("http://www.xmethods.net/sd/CurrencyExchangeService.wsdl")
>lnRate=loExchangeRate.GetRate('United States','Canada')
>

>
>I know of a few clients which have been using it for a few years. As for me, I just started to use it on one of my application and found that it keeps changing overnight. Isn't the exchange rate between those two countries should remain unchanged overnight? Also, if you execute a call to that Web Service from a different ISP or another route, you will get different values. I believe there are some funny responses and based on that I just can't trust that Web Service to get the exchange rate.
>
>Anyone could share some comments on this and some recommendations?