Sample code to get weather info from https://developer.worldweatheronline.com/

weather_api.rb

require 'net/http'
require 'uri'
require 'json'
require 'byebug'
require 'csv'

API_KEY = "xxxx"

# query by lat and lng
# 35.443708,139.638026 is the lat and lng of yokohama city hall

# CSV Output Example
#
# 2016-01-01,12,7,Sunny,1026,41
# 2016-01-02,18,4,Sunny,1022,53
# 2016-01-03,17,10,Sunny,1017,48
# 2016-01-04,19,12,Sunny,1014,63
# ...

dates = [
  {start: '2016-01-01', end: '2016-01-31'},
  {start: '2016-02-01', end: '2016-02-29'},
  {start: '2016-03-01', end: '2016-03-31'},
  {start: '2016-04-01', end: '2016-04-30'},
  {start: '2016-05-01', end: '2016-05-31'},
  {start: '2016-06-01', end: '2016-06-30'},
  {start: '2016-07-01', end: '2016-07-31'},
  {start: '2016-08-01', end: '2016-08-31'},
  {start: '2016-09-01', end: '2016-09-30'},
  {start: '2016-10-01', end: '2016-10-31'},
  {start: '2016-11-01', end: '2016-11-30'},
  {start: '2016-12-01', end: '2016-12-31'},
]


csv = CSV.generate do |csv|
  dates.each do |date|
    start_date = date[:start]
    end_date = date[:end]
    url = "http://api.worldweatheronline.com/premium/v1/past-weather.ashx?key=#{API_KEY}&q=35.443708,139.638026&format=json&date=#{start_date}&enddate=#{end_date}"
    uri = URI.parse(url)
    json = Net::HTTP.get(uri)
    result = JSON.parse(json)
    weather_data =  result['data']['weather']
    weather_data.each do |data|
      weather_desc = data['hourly'][4]['weatherDesc'][0]['value']
      pressure = data['hourly'][4]['pressure']
      humidity = data['hourly'][4]['humidity']
      arr = [data['date'], data['maxtempC'], data['mintempC'], weather_desc, pressure, humidity]
      csv << arr
    end
  end
end

File.open("weather.csv", 'w') do |file|
  file.write(csv)
end