 <p><em>Premise</em>: I really think the ideal way to solve your problem is convert your stored datetimes to UTC, and then use that when you search.</p> <p>But you said you can't change those, so using <code>ConvertTime</code> to convert them at request time is probably your best second option.</p> <ul> <li><a href="https://msdn.microsoft.com/en-us/library/bb382770(v=vs.110).aspx" rel="nofollow">Here</a> you can find all the details you need.</li> <li>You might also want to give a look at <a href="http://nodatime.org/" rel="nofollow">Noda Time</a>, which is quite useful when dealing with TimeZones and DateTime.</li> </ul>