Raspberry Pi Pico W
Asynchronous Web Server

Using the uasyncio library, you can make your webserver asynchronous. I used the same DS18B20 breakout for this as I did for my sensor circuit. In addition to async code, I added a counter to keep track of the number of page views.

Pico Circuit

from time import sleep
from network import WLAN, STA_IF
from secrets import secrets
from machine import Pin
from onewire import OneWire
from ds18x20 import DS18X20
import uasyncio as asyncio

html = """<!DOCTYPE html>
<!DOCTYPE html>
<html lang="en">
<head>
  <title>Temperature Server</title>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.1.3/dist/css/bootstrap.min.css" rel="stylesheet">
  <script src="https://cdn.jsdelivr.net/npm/bootstrap@5.1.3/dist/js/bootstrap.bundle.min.js"></script>
</head>
<body>

<div class="container-fluid p-5 bg-primary text-white text-center">
  <h1>Pico W Temperature Server</h1>
  
</div>
<div class="container-fluid">
  <p>The temperature is %.2f&deg;C.</p>
  <p>Page views: %d.</p>
</div>
<body>
</html>
"""

wlan = WLAN(STA_IF)

# set up temperature sensor with onewire
ow = OneWire(Pin(15))
ds = DS18X20(ow)
r = ds.scan()[0]
t = 0
count = 0


def connect():
    wlan.active(True)
    wlan.config(pm = 0xa11140)
    wlan.connect(secrets["ssid"], secrets["password"])

    # try to connect or fail
    max_wait = 10
    while max_wait >0:
        if wlan.status() <0 or wlan.status()>=3:
            break
        max_wait -= 1
        print("Waiting for connection...")
        sleep(1)

    # connection error
    if wlan.status() != 3:
        return False
    else:
        status = wlan.ifconfig()
        print("Connected to", secrets["ssid"], "on", status[0])
        print()
        return True


async def serve_client(reader, writer):
    global t, count
    request_line = await reader.readline()
    print("Request:", request_line)
    
    # skip HTTP header
    while await reader.readline() != b'\r\n':
        pass
    
    count += 1       
    response = html % (t, count)
    writer.write('HTTP/1.0 200 OK\r\nContent-type: text/html\r\n\r\n')
    writer.write(response)
    
    await writer.drain()
    await writer.wait_closed()
    print("Client disconnected.")

async def main():
    global t
    print("Connecting to network.")
    connect()
    print("Setting up server.")
    asyncio.create_task(asyncio.start_server(serve_client, "0.0.0.0", 80))
    print("Done.")
    while True:
        ds.convert_temp()
        t = round(ds.read_temp(r), 2)
        #print(t)
        await asyncio.sleep(0.25)
        
try:
    asyncio.run(main())
finally:
    asyncio.new_event_loop()

This is the web page shown on a mobile phone connected to the same WiFi network.

Pico Circuit