<nav>
<div class="nav nav-tabs" id="nav-tab" role="tablist">
<button class="nav-link active" id="nav-home-tab" data-bs-toggle="tab" data-bs-target="#january" type="button" role="tab" aria-controls="nav-home" aria-selected="true">Зима</button>
<button class="nav-link" id="nav-profile-tab" data-bs-toggle="tab" data-bs-target="#march" type="button" role="tab" aria-controls="nav-profile" aria-selected="false">Весна</button>
</div>
</nav>
<div class="tab-content" id="nav-tabContent">
<div class="tab-pane fade show active" id="january" role="tabpanel" aria-labelledby="nav-home-tab">Выводится в январе</div>
<div class="tab-pane fade" id="march" role="tabpanel" aria-labelledby="nav-profile-tab">Выводится в марте</div>
</div>
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width">
<title>JS Bin</title>
<style>
.active {
color: red;
}
</style>
</head>
<body>
<div id="january">January</div>
<div id="february">February</div>
<div id="march">March</div>
<div id="april">April</div>
<div id="may">May</div>
<div id="june">June</div>
<div id="july">July</div>
<div id="august">August</div>
<div id="september">September</div>
<div id="october">October</div>
<div id="november">November</div>
<div id="december">December</div>
<script>
let date = new Date();
let month = date.toLocaleString('en', { month: 'long' }).toLowerCase();
document.getElementById(month).classList.add("active");
</script>
</body>
</html>