[arnmPZxRu4]

    Autumn:
        Vendémiaire (from French vendange, derived from Latin vindemia, "vintage"), starting 22, 23, or 24 September
        Brumaire (from French brume, "mist", from Latin brūma, "winter solstice; winter; winter cold"), starting 22, 23, or 24 October
        Frimaire (from French frimas, "frost"), starting 21, 22, or 23 November
    Winter:
        Nivôse (from Latin nivosus, "snowy"), starting 21, 22, or 23 December
        Pluviôse (from French pluvieux, derived from Latin pluvius, "rainy"), starting 20, 21, or 22 January
        Ventôse (from French venteux, derived from Latin ventosus, "windy"), starting 19, 20, or 21 February
    Spring:
        Germinal (from French germination), starting 20 or 21 March
        Floréal (from French fleur, derived from Latin flos, "flower"), starting 20 or 21 April
        Prairial (from French prairie, "meadow"), starting 20 or 21 May
    Summer:
        Messidor (from Latin messis, "harvest"), starting 19 or 20 June
        Thermidor (or Fervidor*) (from Greek thermon, "summer heat"), starting 19 or 20 July
        Fructidor (from Latin fructus, "fruit"), starting 18 or 19 August

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https://en.wikipedia.org/wiki/French_Republican_calendar