And it's official - solar minimum

We still have 74 days until the end of the year but it's looking like we are setting a record. From SpaceWeather:

DEEP SOLAR MINIMUM:
As of today, the sun has been blank (no sunspots) 74% of the time in 2019. This is significant because the previous record for spotlessness during the Space Age was 73% set in 2008. If low sunspot counts continue apace, 2019 could end up as the deepest Solar Minimum of the modern era.

Sunspots are an excellent proxy for solar output. Less sunlight, colder temperatures. SImple as that.