Changes in rainfall seasonality across South Africa may have detrimental impacts on crop yields and surface water supplies. Despite this, these have rarely been investigated across the South African summer‐, winter‐ and year‐round rainfall zones (SRZ, WRZ and YRZ respectively) using consistent methods. Rainfall seasonality changes are explored here using daily rainfall and temperature records for 1987–2016 from 46 meteorological stations spanning a grid across South Africa. Focusing on comparable methods that statistically define the SRZ, WRZ, YRZ, we apply a ratio of monthly rainfall: temperature and a percentile‐based wet‐season start‐ and end‐date metric, which each provide annual outputs of the degree of seasonality, and the timing, duration, magnitude and intensity of wet‐season rainfall. Although relatively few statistically significant trends are detected, some regional spatial patterns are evident. Trends for most locations across the southwestern Cape and western coast are indicative of a decrease in the strength of seasonality with a reduction in winter wet‐season rainfall, and are broadly consistent with observed and projected poleward dynamics of the southern hemisphere subtropical high‐pressure belt and mid‐latitude westerlies. Trends towards later wet‐season start‐dates together with a reduction in summer wet‐season rainfall amount are prominent across most of the interior and northeastern locations, and may be linked to Hadley cell expansion recorded in recent decades. Along the southern coast, trends towards an increase in the degree of seasonality together with a shorter wet‐season, concentrated around the winter months, are evident. If sustained, the trends quantified present a concerning outlook for continued crop production and water resource management, and thus warrant further investigations on rainfall seasonality shifts and the drivers thereof across southern Africa.

Airborne fungal spores and pollen (aerospora), synergistic with air pollution, are key triggers of allergic respiratory diseases. Effective diagnosis and treatment requires up-to-date location-specific knowledge on the temporal variability of aerospora types and levels. Johannesburg is the largest city in South Africa and has grown substantially in three decades, with changes in ground cover, population density and air pollution, yet until now, no continuous aerospora sampling has occurred. We present a daily two-year (August 2019–July 2021) aerospora assemblage for Johannesburg and explore temporal characteristics of 13 dominant aerospora in relation to daily meteorological variables (pressure, rainfall, relative humidity, temperature and wind characteristics). February–July, July–September and January-July represent high-risk periods for fungal spores [(Alternaria alternata (Fries. ex Keissler), Ascospores, Aspergillus niger (Van Tieghem), Penicillium chrysogenum (Thom), Cladosporium graminum (Corda), Epicoccum nigrum (Link), Helminthosporium solani (Durieu and Montagne) Nigrospora sphaerica (Saccardo ex. Mason), Smuts Ustilago nuda (Jensen ex. Rostrup) and Torula herbarum (Link)], trees (Cupressus, Morus and Platanus) and grass (Poaceae), respectively. Using a generalised additive model, results show that daily meteorological characteristics explained 7–32% of daily aerospora variability, with the largest effect on tree pollen. Rainfall, relative humidity and temperature influenced daily fungal spore and Poaceae counts, with moderate/low rainfall (< 20 mm), higher/mid-ranging relative humidity (~ 40–60%) and temperatures of ~ 15–20 °C associated with higher counts during high-risk periods. Rainfall predominantly influenced tree counts during high-risk periods, with higher counts occurring on low rainfall (<10 mm) days. These results update the aerospora profile of Johannesburg, South Africa, providing important information to inform allergy care.