Smoking a cigarette raises the blood pressure by 5-10 mm Hg for about 30 minutes. If this is combined with drinking a cup of coffee, the effects are bigger and last longer.
Despite this, numerous epidemiological studies have found that people with hypertension are not more likely to be smokers than those with normal blood pressure, and conversely, that smokers are not more likely to be hypertensive than non-smokers. One possible explanation for this might be that smokers tend to weigh less than non-smokers, and that the effects of obesity and smoking on blood pressure cancel each other out. But even when smokers and non-smokers of the same body weight are compared their blood pressures are the same. This is probably because the blood pressure measurements are usually made when people are not smoking. If you smoke a pack a day, it will raise your average daytime pressure by about 5 mm Hg, even though your doctor may not detect this during an office visit.
The important thing about smoking is not what it does to your blood pressure, but that it greatly increases your risk of heart disease.