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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2023-01-01</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000783325</issuerCik>
        <issuerName>WEC ENERGY GROUP, INC.</issuerName>
        <issuerTradingSymbol>WEC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001241250</rptOwnerCik>
            <rptOwnerName>STANEK MARY ELLEN</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>231 WEST MICHIGAN STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MILWAUKEE</rptOwnerCity>
            <rptOwnerState>WI</rptOwnerState>
            <rptOwnerZipCode>53203</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable></nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Phantom Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2023-01-01</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>I</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1311.271</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>94.43</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F3"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>1311.271</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>36785.0016</value>
                    <footnoteId id="F4"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">One-for-one.</footnote>
        <footnote id="F2">These phantom stock units were accrued under the WEC Energy Group, Inc. Director's Deferred Compensation Plan (DDCP) and represent an in-service distribution elected by the reporting person pursuant to the terms of the plan.</footnote>
        <footnote id="F3">These phantom stock units were accrued under the DDCP and are to be settled in accordance with the terms of the plan.</footnote>
        <footnote id="F4">Includes phantom stock units accrued pursuant to a dividend reinvestment feature of the DDCP in transactions exempt from Section 16 pursuant to Rule 16a-11.</footnote>
    </footnotes>

    <remarks>Exhibit List: Exhibit 24-Power of Attorney</remarks>

    <ownerSignature>
        <signatureName>Joshua M. Erickson, as attorney in fact</signatureName>
        <signatureDate>2023-01-04</signatureDate>
    </ownerSignature>
</ownershipDocument>
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X0306
4
2023-01-01
0
0000783325
WEC ENERGY GROUP, INC.
WEC
0001241250
STANEK MARY ELLEN
231 WEST MICHIGAN STREET
MILWAUKEE
WI
53203
1
0
0
0
Phantom Stock Units
2023-01-01
4
I
0
1311.271
94.43
D
Common Stock
1311.271
36785.0016
D
One-for-one.
These phantom stock units were accrued under the WEC Energy Group, Inc. Director's Deferred Compensation Plan (DDCP) and represent an in-service distribution elected by the reporting person pursuant to the terms of the plan.
These phantom stock units were accrued under the DDCP and are to be settled in accordance with the terms of the plan.
Includes phantom stock units accrued pursuant to a dividend reinvestment feature of the DDCP in transactions exempt from Section 16 pursuant to Rule 16a-11.
Exhibit List: Exhibit 24-Power of Attorney
Joshua M. Erickson, as attorney in fact
2023-01-04