I realised that while the “Standard” plan for MeteoSource is a whopping £60 per month for 20,000 calls per day, but it also has a 10 day free trial.
So I signed up for the free trial and downloaded 365 days of temperature data for where I live.
There is hourly data for each day, along with a daily summary:
"daily": {
"temperature": -0.4,
"temperature_min": -2.2,
"temperature_max": 2,
"feels_like": -2.9,
"feels_like_min": -4.4,
"feels_like_max": -1.1,
"wind_chill": -3.9,
"wind_chill_min": -5.5,
"wind_chill_max": -2.4,
"soil_temperature": 2,
"soil_temperature_min": 0.6,
"soil_temperature_max": 3.5,
"dew_point": -4.7,
"dew_point_min": -7.8,
"dew_point_max": -0.8,
"surface_temperature": 0.9,
"surface_temperature_min": -0.8,
"surface_temperature_max": 3.8,
"wind": {
"speed": 3.2,
"gusts": 8.7,
"dir": "NW",
"angle": 305
},
"cloud_cover": {
"total": 12,
"low": 5,
"middle": 12,
"high": 20
},
"pressure": 1011,
"precipitation": {
"total": 0,
"type": "none"
},
"humidity": 74
},
So I have what I need now
However not seeing much of a correlation between the outside temperatures and my gas bill