Sydney Summer Heat by Suburb

The headline

A 4.2 degree gradient across one city

Sydney is usually forecast as a single place. It is not. On an average January day Penrith Lakes reaches 31.2 degrees while Observatory Hill on the harbour reaches 27.0, a difference of 4.2 degrees that holds right through summer.

Winter runs the other way and further. Camden Airport averages a July minimum of 3.2 degrees against 8.9 at Sydney Observatory Hill, a 5.7 degree spread. The inland suburbs are both the hottest in summer and the coldest at night in winter.

January mean maximum, by station

Why the period matters

Most comparisons of Sydney temperatures are wrong, and for a subtle reason. Observatory Hill has recorded since 1859 and its all-years January average is 26.0 degrees. Modern automatic stations have twenty or thirty years of record. Comparing the two measures the warming trend and the length of the record, not the geography.

Every figure on this page uses the standard 1991 to 2020 normals, the same window at every station, which is the only way the comparison holds. It also means some stations are missing: Holsworthy Aerodrome, Sydney Olympic Park and Lucas Heights have no qualifying normals, so nearby stations stand in for those suburbs.

What it means for sizing an air conditioner

Cooling capacity is specified against a design temperature. A system sized off a generic Sydney figure is being designed for the harbour, and in Penrith Lakes that is 4.2 degrees optimistic on the days that matter most. The result is a unit that holds a room on a mild day and loses it on a hot one.

The winter numbers matter just as much for reverse cycle. At a July minimum of 3.2 degrees, heating output at low ambient temperature stops being a specification detail and becomes the reason to choose one system over another.

Using this data

The figures are the Bureau of Meteorology's, published under Creative Commons Attribution. This page is the arrangement of them, and you are welcome to cite it, quote the numbers or reproduce the table. A link back is appreciated but not required.

Suggested citation: Sydney Heating & Cooling, “Sydney Summer Heat by Suburb”, from Bureau of Meteorology climate statistics, 1991–2020 normals. https://sydneyheatingcooling.com.au/sydney-suburb-heat-data/

Source tables are public at bom.gov.au/climate/averages/tables, searchable by the station numbers listed above. If you are writing about Sydney heat and want the underlying figures in another format, get in touch and we will send them over.