Table 2.

Seasonal mean temperature correlated with malaria cases in 1800–1870

Season correlated with malaria cases in 1800–1870	Source of temperature series
	Helsinki 1830–1870 41 years	Tornedalen 1818–1870 53 years	Stockholm 1800–1870 71 years	St. Petersburg 1806–1870 65 years
malaria year-1; winter	-0.1932	-0.1209	-0.1652	-0.0789
malaria year-1; spring	-0.0091	-0.0228	0.0248	-0.0312
malaria year-1; summer	0.5120 ***	0.5208 ***	0.4708 ***	0.3981 ***
malaria year-1; autumn	0.1218	0.1621	0.1055	0.1598
malaria year; winter	-0.1254	-0.0743	-0.1214	-0.1543
malaria year; spring	0.1140	0.0880	0.0223	0.0546
malaria year; summer	-0.0740	-0.0332	0.0201	-0.0439
malaria year; autumn	-0.0831	-0.0819	-0.0211	-0.0797