Objective To analyze the effects of meteorological factors on the incidence of scarlet fever in Guangzhou from 2014 to 2022.

Methods The epidemiological characteristics of scarlet fever in Guangzhou were described. The effects of meteorological factors on the risk of scarlet fever were evaluated via Spearman correlation analysis, distributed lag non-linear models, and bivariate response models.

Results The incidence of scarlet fever had correlations (P < 0.05) with mean temperature (rs = −0.255), wind speed (rs = −0.126), air pressure (rs = 0.116), and sunshine duration (rs = −0.177). Mean temperature exhibited risk effects at lower temperatures and protective effects at higher temperatures, with the relative risk (RR) peaking at 1.41 (95%CI: 1.09–1.83) when the temperature was 12 ℃. The relationships of wind speed and sunshine duration with incidence of scarlet fever followed a wave-like pattern, with the strongest risk effect observed at a wind speed of 4.3 m/s (RR = 5.67, 95%CI: 1.61–19.84). When sunshine duration exceeded 8 h/d, the risk effect increased markedly, albeit not statistically significant (95%CI: 0.97–4.95). Air pressure demonstrated protective effects at low levels and risk effects at high levels on the incidence of scarlet fever, with the RR peaking at 2.26 (95%CI: 1.70–3.02) when the air pressure was 1 016.5 hPa. The interactions of meteorological factors such as low temperature, high wind speed, long sunshine duration, and high air pressure further contributed to an increase in scarlet fever incidence in Guangzhou.

Conclusions Mean temperature, wind speed, air pressure, and sunshine duration demonstrate non-linear relationships and lag effects with the incidence of scarlet fever, with interactions among each other. Therefore, adjusting these meterological factors can be taken as a focus of prevention and control efforts for scarlet fever.