<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2005-04-11</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000075129</issuerCik>
        <issuerName>OTTER TAIL CORP</issuerName>
        <issuerTradingSymbol>OTTR</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001191494</rptOwnerCik>
            <rptOwnerName>MACFARLANE JOHN C</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>215 S CASCADE ST</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>FERGUS FALLS</rptOwnerCity>
            <rptOwnerState>MN</rptOwnerState>
            <rptOwnerZipCode>56537-2801</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2005-04-11</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1300</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>24.93</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3100</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Shares of Common Stock acquired under the Corporation's Stock Incentive Plan, which is a grant of Restricted Stock.  The 1,300 shares granted 4/11/05 have a grant price of $24.93 and vest at 25% yearly beginning 4/8/06.  See below for other holdings:
1.  Direct holding of 2,525 shares held jointly with his wife.
2.  Direct holding of 22,744.3587 shares held in the Dividend Reinvestment Plan.
3.  Direct holding of 2,258.9495 shares held in the Employee Stock Purchase Plan.
4.  Direct holding of 8,151 shares which no longer carries the restriction.
5.  Indirect holding of 19,483.1671 shares held by ESOP.
6.  Indirect holding of 3,311.5490 shares held by an IRA.
7.  52,000 stock options with expiration date of 2/22/2009.
8.  100,000 stock options with expiration date of 4/9/2010.
9.  100,000 stock options with expiration date of 4/8/2011.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ John C MacFarlane by Debra J Lill -POA</signatureName>
        <signatureDate>2005-04-13</signatureDate>
    </ownerSignature>
</ownershipDocument>
