Volume 43 - Article 40 | Pages 1185–1198  

The geographical patterns of birth seasonality in Australia

By Tom Wilson, Peter McDonald, Jeromey Temple

Abstract

Background: Studies have shown how births exhibit seasonal patterns, with peaks and troughs in particular months and seasons. Most of this literature focuses on national-level patterns mainly in countries of the northern hemisphere.

Objective: The aim of the paper is to describe key features of contemporary birth seasonality at a subnational scale across Australia.

Methods: Data on births across the year by region for the 2001‒2016 period were acquired from the Australian Bureau of Statistics. A Births Index was calculated to standardise for length of month and variations in birth numbers between regions. Choropleth maps and graphs were used to illustrate the geographical patterns.

Results: Birth seasonality across Australia’s regions is moderate but the patterns vary in a strongly clustered way. In northern and central latitudes of Australia, births are above-average early in the year (February to April), while in the southeast of the country they tend to be above-average in September and October.

Conclusions: The Australian results are consistent with physiological hypotheses that climate and environmental influences have a role in the seasonality of births. Hot and humid summers in northern Australia, and cold winters in the southernmost parts of the country, might be responsible for reducing the number of conceptions below their regional averages for the year.

Contribution: We demonstrate how birth seasonality across the regions of Australia has a strong climatic pattern that is consistent with physiological hypotheses.

Author's Affiliation

Other articles by the same author/authors in Demographic Research

Projecting the sexual minority population: Methods, data, and illustrative projections for Australia
Volume 45 - Article 12

Preparing local area population forecasts using a bi-regional cohort-component model without the need for local migration data
Volume 46 - Article 32

Subnational population forecasts: Do users want to know about uncertainty?
Volume 41 - Article 13

Visualising the demographic factors which shape population age structure
Volume 35 - Article 29

An assessment of recent Iranian fertility trends using parity progression ratios
Volume 32 - Article 58

What happens after you drop out? Transition to adulthood among early school-leavers in urban Indonesia
Volume 30 - Article 41

Societal foundations for explaining fertility: Gender equity
Volume 28 - Article 34

The sequential propensity household projection model
Volume 28 - Article 24

Model migration schedules incorporating student migration peaks
Volume 23 - Article 8

Australia's uncertain demographic future
Volume 11 - Article 8

Most recent similar articles in Demographic Research

The big decline: Lowest-low fertility in Uruguay (2016–2021)
Volume 50 - Article 16    | Keywords: adolescent fertility, birth order, fertility, Latin America, ultra-low fertility, Uruguay

Cohort fertility of immigrants to Israel from the former Soviet Union
Volume 50 - Article 13    | Keywords: age at first birth, assimilation, cohort analysis, fertility, immigration, parity, religiosity

Fertility decline, changes in age structure, and the potential for demographic dividends: A global analysis
Volume 50 - Article 9    | Keywords: age structure, demographic dividend, demographic transition, fertility, migration, population momentum, working-age population

Analyzing hyperstable population models
Volume 49 - Article 37    | Keywords: birth trajectory, cohort analysis, cyclical populations, dynamic population model, fertility, hyperstable, period

Changes in birth seasonality in Spain: Data from 1863–1870 and 1900–2021
Volume 49 - Article 35    | Keywords: Box-Jenkins method, Cosinor analysis, Fourier analysis, season of birth, seasonality, time series, vital statistics