Seasonal variance and climatic factors interrelated in incidence of psychiatric disorders and suicide have been attracting attention of resarchers for centuries. Still there are known just a few studies on the topic, once accomplished in remote times and parts of the world, which results might be found just controversial.

This pilot study analyses correlations in one year data on acute psychiatric admissions and suicides along with many objective physical parameters.

Used data are collected from two main psychiatric hospitals in Prague (1.5 mil. inhabitants), scientific institutes of Czech Academy of Science and Czech statistical office. Daily numbers of acutely admitted psychiatric patients during the year of 2005 (N = 3304) and suicides (N = 152) include persons of productive age, both gender, 18-65 years old. The daily admission rates, suicides and their distribution during the year and many climatic objective variables are treated with contemporary statistical methods.

Acute daily psychiatric admission rate seems to be significantly correlated with maximal daily temperature (x2, p= 0.05), quarters of the year (anova, p=0.003; x2, p=0.034), days of week (anova, p=0.001), weekends (t-test, p=0.0001), bank holidays (t-test, p=0.048).

Daily numbers of suicide do not significantly correspond with the variables meant above.

The strongest finding seems to be high risk of suicide in low air humidity condition: ODDS = 1.76.

Daily incidence of suicidality and acute psychiatric disorders differ in seasonal distribution and supposed relations to climatic factors. The study in wider complexity to be continued.