Rathmullan Temperature by Month

The average annual maximum temperature in Rathmullan, Donegal County, Ireland is 14°C (57°F), with daytime highs ranging from 9°C (48°F) in January to 19°C (66°F) in July. This page covers monthly averages, day-night differences, and how Rathmullan compares to cities worldwide.

Rathmullan experiences balanced seasonal shifts, with noticeable but moderate temperature variations. At night, minimum temperatures range from 12°C (54°F) in July to 4°C (39°F) in January.

The chart below illustrates the average maximum day and minimum night temperatures in Rathmullan by month:

Low temperatures are most often recorded between 4 AM and 6 AM, while highs typically occur around 3 PM. July, the city's warmest month, sees 141 hours of sunshine.

The chart below shows the average temperature throughout the year:

Rathmullan's average annual maximum temperature is 14°C (57°F). To put that in context, here's how it compares to a few well-known destinations:

Lisbon, Portugal averages 21°C (70°F) annually, warm summers, mild winters, and rain mainly in the cooler months.

Zermatt, Switzerland averages just 4°C (39°F) annually due to its altitude, with very cold winters and cool summers even at its warmest.

Beijing, China averages 20°C (68°F) annually, but with big seasonal swings, very cold winters and hot summers.

Tokyo, Japan averages 21°C (70°F) a year, with hot summers, cool winters, and a well-defined cherry blossom spring.

Climate temperature data is typically calculated as a 30-year average. This smooths out year-to-year variability and gives a more reliable picture of what a place is actually like, rather than what happened in any single unusual year.

The readings come from a range of sources, land-based weather stations, ocean buoys, ships, and satellites. That data is collected by weather services around the world, then pooled, quality-checked, and averaged to produce the climate records you see here.

Land Temperature: The average surface temperature across the Earth's land is around 14°C, but that figure hides enormous variation. In the Sahara, daytime temperatures can exceed 50°C. At the poles, averages fall below -30°C. Deserts are also notable for how quickly they cool at night, without moisture in the air to retain heat, temperatures can drop 30°C or more in just a few hours, making desert nights surprisingly cold.

Sea Temperature: The oceans average around 17°C at the surface, generally cooler than land. Because water absorbs and releases heat slowly, the sea acts as a buffer, keeping coastal climates more stable than inland areas. The deep ocean is a different story: below the sunlit upper layers, water stays near-freezing regardless of surface conditions.

Equatorial Regions: Near the equator, the sun is overhead year-round, producing consistent heat and fuelling tropical rainforests in places like the Amazon and Congo basins. Seasonal temperature variation is minimal, but these regions do experience distinct wet and dry seasons that shape their ecosystems.

Desert Regions: Desert temperatures swing wildly between seasons and even between day and night. The Sonoran Desert in North America can drop to 0°C on winter nights yet exceed 40°C on summer days. What all deserts share is very low rainfall, typically under 250mm per year.

Polar Regions: The Arctic and Antarctic experience extreme cold, with long stretches of darkness in winter and continuous daylight in summer. Arctic winter temperatures average around -30°C. In Antarctica's interior, it gets far colder, sometimes below -80°C in the coldest recorded spots.

Temperate Forests: Across North America, Europe, and East Asia, temperate forests see proper seasons, warm summers and cold winters, with average temperatures roughly between 5°C and 22°C depending on the time of year.

Mountain Regions: Temperature drops by roughly 6°C for every 1,000 metres of altitude. In ranges like the Andes or the Himalayas, that means you can move from temperate forest at lower elevations to permanent snow and ice at the peaks, all within a relatively short distance.

For more on Rathmullan's weather, including monthly rainfall, sunshine hours, and humidity, visit our Rathmullan climate page.