The independent influence of seasonal and weather factors on cardiovascular morbidity and mortality is well known. One of the causes of this phenomenon may be seasonal blood pressure (BP) variations demonstrated by both clinical measurements and, later, 24-hour BP monitoring (BPM). However, the conducted investigations have a number of limitations: a single-step pattern, the preferred use of either clinical or ambulatory BP measurements. In addition, such investigations with a detailed analysis of different BP indicators have not been performed in the Russian Federation characterized by a large territory and a variety of climatic zones. The paper describes the design and preliminary results of a prospective comparative study of the relationship of BP levels and vascular rigidity in patients with hypertension or in those with prehypertension to seasonal and climatic factors (the influence of a temperature factor is to be primarily evaluated). The study is being conducted in two regions (Ivanovo and Saratov) of the Russian Federation, which are characterized by significant temperature differences. The paper details the original protocol and methods involving a double examination of patients with hypertension and those with prehypertension at a 6-month interval, by applying standard procedures (detailed history data collection, anthropometry, clinical BP recording, and 24-hour BPM) and by estimating the parameters of arterial rigidity. Analysis of preliminary data suggests that there are seasonal and interregional differences in BP levels. Completion of material collection and publication of basic results are scheduled for late 2014. The findings will be able to elaborate measures for the primary and secondary prevention of hypertension in relation to seasonal and temperature factors.