JSFiddle - React, Tailwind, and code Playground

HTML

<div class="table-wrapper">
    <table id="consumption-data" class="data">
        <thead class="header">
            <tr>
                <th>Month</th>
                <th>Item 1</th>
                <th>Item 2</th>
                <th>Item 3</th>
                <th>Item 4</th>
                
                  <th>Item 5</th>
                <th>Item 6</th>
                <th>Item 7</th>
                <th>Item 8</th>
                
                  <th>Item 9</th>
                <th>Item 10</th>
                <th>Item 11</th>
                <th>Item 12</th>
                
                  <th>Item 13</th>
                <th>Item 14</th>
                <th>Item 15</th>
                <th>Item 16</th>
                
                  <th>Item 17</th>
                <th>Item 18</th>
                <th>Item 19</th>
                <th>Item 20</th>
            </tr>
        </thead>
        <tbody class="results">
            <tr>
                <th>Jan</th>
                <td>3163</td>
                <td>3163</td>
                <td>3163</td>
                <td>3163</td>
                <td>3163</td>
                <td>3163</td>
                <td>3163</td>
                <td>3163</td>
                <td>3163</td>
                <td>3163</td>
                <td>3163</td>
                <td>3163</td>
                <td>3163</td>
                <td>3163</td>
                <td>3163</td>
                <td>3163</td>
                <td>3163</td>
                <td>3163</td>
                <td>3163</td>
                <td>3163</td>
            </tr>
            
                 <tr>
                <th>Jan</th>
                <td>3163</td>
                <td>3163</td>
                <td>3163</td>
                <td>3163</td>
                <td>3163</td>
                <td>3163</td>
                <td>3163</td>
                <td>3163</td>
                <td>3163</td>
                <td>3163</td>
               ...

CSS

.table-wrapper { 
overflow:auto;
 
}
.header{float:left;width:100%;background:#fff;height:60px;}
.header tr{position:fixed;background:#fff;}



th:first-child {
      position: fixed;
    left: 5px
}