Oslo in June: June marks the meteorological start of summer with long days, rising temperatures, and increasing thunderstorms that replace the frontal rainfall of spring. Oslo on the Oslofjord has a humid continental climate with around 1700 sunshine hours per year, a January average of -4°C and around 760 mm of annual precipitation. Climate change is leaving visible traces here too: deviations from the long-term mean reveal how weather extremes in Oslo have shifted over the past decades.
June in Oslo typically shows summer warmth and the first thunderstorm episodes. Deviations from the 10-year average reveal how the local climate is changing.
Planning around June in Oslo? This page shows the average weather in Oslo during June 2025, compared against the 10-year climatological mean. The comparison covers daily maximum and minimum temperature, sunshine hours, precipitation, and peak wind speed. Those five variables most reliably describe whether a month felt warmer, sunnier, wetter or windier than usual.
Historical weather data for Oslo comes from the ERA5 reanalysis product, a high-resolution dataset maintained by the European Centre for Medium-Range Weather Forecasts (ECMWF) and delivered through Open-Meteo. ERA5 is one of the most accurate publicly available sources for historical Oslo climate values, updated daily and covering every month from 1940 to today. That means typical Oslo June conditions are grounded in measured values, not a statistical model.
The KPI cards on this page each show two numbers: the current June 2025 value for Oslo, and its deviation from the 10-year reference mean. A positive deviation means the month ran warmer, sunnier, wetter or windier than the recent climate normal for Oslo in June. Weather in Oslo Junehas shifted measurably over recent decades; to explore Oslo June climate year by year, open the climate trend page. To compare Oslo weather against another city for the same month, use the weather comparison tool.
This page is a retrospective, not a forecast. If you are planning travel, a garden project, a photo shoot, or an event in Oslo in June, use the measured historical values as a realistic baseline and treat them as a distribution, not a guarantee. The 10-year mean smooths over individual extreme years; the current-year values show where this particular June sat against that baseline. For typical Oslo June conditions across a longer window, the climate trend page covers every year back to 1940. For day-level detail rather than monthly aggregates, compare arbitrary date ranges for Oslo using the period comparison tool on the homepage.
This page compares the daily measured values of the current year against the average of the last ten years, the so-called 10-year mean. The deviation values in the KPI cards show directly whether the current month is warmer, sunnier, wetter, or windier than usual. The reference data comes from Open-Meteo's ERA5 weather archive and includes daily measured maximum and minimum temperatures, sunshine hours, precipitation totals, and wind speeds.
A ten-year average is short enough to reflect current climate trends, yet long enough to statistically balance out individual extreme years. The World Meteorological Organization (WMO) recommends 30-year normals as the official climate reference, our 10-year mean is deliberately more present-focused and therefore shows the climate change of the most recent decade more clearly.
The daily data for the current year comes directly from Open-Meteo in real time. The reference mean is calculated from actual measured values of the last 10 years, no statistical model, but real historical archive data. The basis is ECMWF's ERA5 reanalysis dataset.
The deviation shows the difference between the current monthly average and the 10-year reference value for the same month. A value of +2.3 °C means: the current month is on average 2.3 degrees warmer than the average of the last 10 years.
Weather review pages are available for over 100 cities in Germany, Austria, and Switzerland. Choose your city from the overview page or use the weather comparison tool on the homepage for custom periods.