Build a Desktop Weather App with Python and PyQt5 – Full Step‑by‑Step Guide

Development Environment

Python 3

PyQt5

requests

Preparing City Code Data

Download the city‑code CSV from the HeWeather website, then use pandas to read the file, keep the City_ID and City_CN columns, and extract the numeric part of the ID.

import pandas as pd
# 将下载好的文件命名为 'city_code.csv'
file = pd.read_csv('city_code.csv')
# 选取需要的两列信息
file = file.loc[:,['City_ID', 'City_CN']]
# 读取前五行信息
file.head()

Convert the ID strings to pure numbers, build a mapping dictionary, and store it as city_code.txt for later reuse.

# 匹配 City_ID 中的数字
def convert(x):
    pat = re.compile('(\d+)')
    return pat.search(x).group()

file['City_ID_map'] = file['City_ID'].map(convert)

# 建立城市与代码之间的映射关系
def city2id(file):
    code_dict = {}
    key = 'City_CN'
    value = 'City_ID_map'
    for k, v in zip(file[key], file[value]):
        code_dict[k] = v
    return code_dict

code_dict = city2id(file)

# 将所得的字典数据存储为 txt 文件
import json
filename = 'city_code.txt'
with open(filename, 'w') as f:
    json.dump(code_dict, f)

Loading the dictionary later is straightforward:

with open(filename, 'r') as f:
    text = json.load(f)

UI Design

The interface is created with Qt Designer; the resulting window includes a line edit for the city name, a read‑only text edit for output, and a query button.

Main Logic – Querying the Weather API

The application calls the public API http://wthrcdn.etouch.cn/weather_mini?citykey={code}, where {code} is the numeric city identifier obtained earlier. The response is JSON.

def query_weather(code):
    # 模板网页
    html = f'http://wthrcdn.etouch.cn/weather_mini?citykey={code}'
    # 向网页发起请求
    try:
        info = requests.get(html)
        info.encoding = 'utf-8'
    except requests.ConnectionError:
        raise
    # 将获取的数据转换为 json 格式
    try:
        info_json = info.json()
    except JSONDecodeError:
        return '无法查询'
    # 提取需要的天气信息
    data = info_json['data']
    city = f"城市：{data['city']}
"
    today = data['forecast'][0]
    date = f"日期：{today['date']}
"
    now = f"实时温度：{data['wendu']}度
"
    temperature = f"温度：{today['high']} {today['low']}
"
    fengxiang = f"风向：{today['fengxiang']}
"
    type = f"天气：{today['type']}
"
    tips = f"贴士：{data['ganmao']}
"
    return city + date + now + temperature + fengxiang + type + tips

Widget Methods Used

self.textEdit.setReadOnly(True)
self.lineEdit.setFocus()
city = self.lineEdit.text()
self.textEdit.setText(info)
self.lineEdit.clear()

Shortcut Key for Query

def keyPressEvent(self, e):
    # 设置快捷键
    if e.key() == Qt.Key_Return:
        self.queryWeather()

Packaging the Application

After the program works, package it with pyinstaller -w weather.py. Remember to copy city_code.txt into the dist/weather folder so the executable can locate the city‑code dictionary.