Colors of the following climate diagrams: United States United Kingdom
Daily maximum temperatures
The highest daytime temperatures in the United Kingdom are reached in July with an average of 19.0 °C. The coldest month, on the other hand, is January, with an average of just 7.2 °C. In the United States, July is the warmest month, with 30.8 °C. There, it is coolest in January with an average of 6.0 °C.
Night time lows
At night, it cools down to varying degrees depending on the country and altitude. In the United Kingdom, temperatures drop as low as 2.7 °C in February. The warmest nights are in July at 12.1 °C. In the United States, it is coolest at night in January at -4.2 °C and warmest in July at 18.8 °C. This corresponds to a cooling of 4.1 to 7.2 °C in the United Kingdom and 9.8 to 12.5 °C in the United States.
The humidity of the air depends to a large extent on the air temperature. The warmer the air, the more water it can absorb. At a temperature of 25°C it is 23 grams per cubic meter, at 30 degrees it is already 26 grams. Therefore, the air humidity is given as a relative value to the temperature-dependent maximum amount. It becomes unpleasant when high humidity is combined with high temperatures.
Humidex is an approximate, sensed temperature calculated on the basis of air temperature, dew point and humidity. It was developed in 1965 by the Canadian meteorologists J. M. Masterton and F. A. Richardson. Since the wind speed is ignored here, it is not very meaningful in areas below approx. 15°C. Above that, it is more reliable, since at higher temperatures humidity plays a greater role than wind.
Rain days per month
By definition, a rain day is a day on which at least 0.1 liters of precipitation per m² fall. This corresponds to a 1 square meter puddle in which the water stands 0.1 mm high — insofar as the water does not seep away or evaporate. So it does not have to rain all day long. December brings the most rainy days (15.9) in the United Kingdom. With an average of only 10.4 days, April is the friendliest. In the United States, it rains most often in May with 8.3 days.
Precipitation amount per day
Depending on the season and the location of a country, the wind brings a varying amount of water with it. As a rule, the water evaporating in the oceans is absorbed and then transported inland. The greatest amount of rain (hail or dew are also forms of precipitation) in the United Kingdom occurs in November, when about 3.3 liters per square meter fall per day. In the United States, the average amount of precipitation ranges from 1.9 liters per day in January to 3.1 in June. However, these are average values. If you consider that there are only 7.9 rainy days in the United States in June, each of them accounts for about 11.6 liters.
Sunshine hours per day
With 2,628 hours of sunshine per year, the United States is in the lead. The most hours of sunshine (9.7 per day) are in July. The United Kingdom falls into second place with only 1,387 hours. There the sun is visible in December for only 1.5 hours per day, so not hidden behind clouds.
Hours of daylight
The length of a day varies throughout the year and depends on the distance from the equator. In December, the day in the United Kingdom is only 7.4 hours long. In June, on the other hand, it is 17.4 hours. In the United States, it is 9.2 hours in December and 15.3 in June.