What were records like in the 10s, 20s and 30s?

The temperature record for Canada is from the 30s.

Do we have good accurate records from then

You can search for historical weather records on https://climate.weather.gc.ca. You can find weather stations going back to the 1800s.

What were records like in the 10s, 20s and 30s?

Not that high. The 34°C back in 2009 was the highest temperature ever measured in Vancouver.

Do we have good accurate records from then

You can search for historical weather records on https://climate.weather.gc.ca. This is the oldest weather station in Vancouver as far as I know. Goes back to 1898.

https://climate.weather.gc.ca/climate_data/daily_data_e.html?hlyRange=%7C&dlyRange=1898-10-01%7C1979-05-31&mlyRange=1898-01-01%7C1979-12-01&StationID=898