| Average climate data for Geysir, Iceland | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
| Average maximum temperature (°F) | 29 | 29 | 31 | 36 | 42 | 50 | 52 | 51 | 44 | 37 | 31 | 27 | 52 |
| Average minimum temperature (°F) | 21 | 21 | 21 | 26 | 32 | 39 | 42 | 41 | 36 | 30 | 24 | 18 | 18 |
| Average precipitation (inch) | 6 | 4 | 5 | 3 | 2 | 2 | 2 | 3 | 5 | 4 | 3 | 5 | 43 |
| Average rainfall days (days) | 15 | 12 | 14 | 17 | 17 | 17 | 21 | 19 | 22 | 19 | 15 | 13 | 202 |
| Average snowfall (inch) | 15 | 9 | 15 | 5 | 1 | 0 | 0 | 0 | 1 | 2 | 6 | 10 | 65 |
| Average snowfall days (days) | 17 | 14 | 17 | 12 | 4 | 0 | 0 | 0 | 1 | 6 | 12 | 16 | 99 |
| Average relative humidity (%) | 89 | 88 | 87 | 85 | 80 | 79 | 80 | 81 | 87 | 88 | 87 | 87 | 85 |
| Average wind speed (mph) | 12 | 12 | 11 | 11 | 10 | 7 | 7 | 8 | 10 | 11 | 11 | 12 | 10 |
| Average daily daylight hours (h) | 5 | 8 | 11 | 15 | 18 | 21 | 19 | 16 | 13 | 9 | 6 | 4 | 12 |
| Average daily sunshine hours (h) | 2 | 3 | 4 | 5 | 7 | 6 | 7 | 8 | 4 | 4 | 2 | 2 | 5 |
| Average cloud coverage (%) | 65 | 64 | 64 | 65 | 58 | 57 | 59 | 57 | 66 | 61 | 60 | 58 | 61 |
| Average UV index | 2 | 2 | 2 | 2 | 2 | 3 | 3 | 2 | 2 | 1 | 1 | 2 | 2 |
The warmest month, with the highest average maximum temperature, is July (52.4 °F). The month with the lowest average maximum temperature is December (27.3 °F). Overall, the average maximum temperature over the whole year is 38.3 °F.
The month with the highest average minimum temperature is July (42.4 °F). The coldest month, with the lowest average minimum temperature, is December (18.5 °F). Overall, the average minimum temperature over the whole year is 29.4 °F.
The wettest month, with the highest amount of precipitation, is January (5.5 inch). The driest month, with the least amount of precipitation, is June (1.6 inch). Over the whole year there are 43.3 inch of rainfall on average.
The month with the most days of rain is September (21.8 days). The month with the fewest days of rain is February (12.3 days). Over the whole year there are 202 days of rain on average.
The month with the most snowfall is January (15.4 inch). The months with the least snowfall are June, July and August (0 inch). Over the whole year there are 65.4 inch of snowfall on average.
The month with the most days of snowfall is March (17.3 days). The months with the fewest days of snowfall are July and August (0 days). Over the whole year there are 99.2 days of snowfall on average.
The month with the highest average relative humidity is January (88.5 %). The month with the lowest average relative humidity is June (78.9 %). The overall average relative humidity over the whole year is 84.7 %.
The windiest month, with the highest average wind speed, is February (12.3 mph). The calmest month, with the lowest average wind speed, is June (7.3 mph). The overall average wind speed over the whole year is 10.1 mph.
The month with the cloudiest skies, so the highest cloud coverage, is September (66.2 %). The month with the clearest skies, so the lowest cloud coverage, is August (57.1 %). Over the whole year there is an average cloud coverage of 61.2 %.
The month with the longest days, so the most daylight, is June (Average daylight: 21 h). The month with the shortest days, so the least daylight, is December (Average daylight: 4 h). Over the whole year there are 12.1 h of daylight per day on average.
The month with the most sunshine per day is August (Average sunshine: 7.9 h). The month with the least sunshine per day is November (Average sunshine: 2 h). Over the whole year there are 4.5 h of sunlight per day on average.
The months with the highest average UV index are June and July (UV index: 3). The months with the lowest average UV index are October and November (UV index: 1). Over the whole year the average UV index is 2.
