How can I view the current blockchain size? How can I view the current size, preferably in bytes, of the blockchain? Is there a CLI command for bitcoind? Or a website that displays the size?
If you have the bitcoin client running in server mode, you can pass it the getblockchaininfo command. This is the current output:

{
  "chain": "main",
  "blocks": 525329,
  "headers": 525329,
  "bestblockhash": "000000000000000000192cf4d557fb2265855713b0fd208a6490bca81137bce4",
  "difficulty": 4306949573981.513,
  "mediantime": 1527792344,
  "verificationprogress": 0.9999976722383654,
  "chainwork": "000000000000000000000000000000000000000001e6cf0d64537cc800fc54f8",
  "pruned": false,
  "softforks": [
    {
      "id": "bip34",
      "version": 2,
      "reject": {
        "status": true
      }
    },
    {
      "id": "bip66",
      "version": 3,
      "reject": {
        "status": true
      }
    },
    {
      "id": "bip65",
      "version": 4,
      "reject": {
        "status": true
      }
    }
  ],
  "bip9_softforks": {
    "csv": {
      "status": "active",
      "startTime": 1462060800,
      "timeout": 1493596800,
      "since": 419328
    },
    "segwit": {
      "status": "active",
      "startTime": 1479168000,
      "timeout": 1510704000,
      "since": 481824
    }
  }
}


The blocks field is the current number of blocks in the block chain. You can also get this information from BlockExplorer or use the Direct Link to the block count.

If you want the size in bytes, look at the size of your blk0001.dat file, currently 528Mb.