Weather in Glasgow in September

Shoulder season. September is shoulder season in Glasgow — cheaper, quieter, and a genuine gamble. You should expect rain on 18 days of the month, which is more days wet than dry.

September ranks 4 of 12 in Glasgow: past the worst of the year but short of July, which is the month to book if the dates are open.

Rain on 18 days, 3 of them heavy. Enough to need a plan B, not enough to need a plan around it. Pack for 15.5 °C days and 9.5 °C nights; the spread matters more here than any single number.

What the averages hide

Averages flatten a month, and this one hides a few things: the day barely swings — 6 °C between the overnight low and the afternoon high. Across the twenty years measured, the hottest September day reached 23.2 °C and the coldest night fell to 1.5 °C, and the wettest single day dropped 26 mm — roughly 25% of the month's rain in one day.

September is statistically steady but not small: the year-to-year variation is modest in relative terms, yet the wettest September on record still delivered 187 mm against 26 mm in the driest. In a month this wet, even a tame spread is a lot of rain in absolute terms — the 106 mm average is a reasonable planning figure, not a promise.

Wind is light at 12.4 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 90%, high enough to notice on the warm days without dominating them.

How September sits in the year

The month is on the way down: 2.1 °C cooler than August, with October dropping another 3.4 °C. The first week and the last are not the same trip.

Daylight in September

12.9 hours of daylight, losing 2.3 hours across the month. That is between Glasgow's extremes of 17.5 and 7 hours, so days are long enough not to constrain the plan.

An inland climate

Despite being inland, the year stays fairly even: 16.1 °C between the year's warmest afternoons and coldest nights.

How busy it gets

Busy. Popular without being frantic; book the things you care about, improvise the rest.

Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.

September in Glasgow versus nearby

If Glasgow is one option among several, the nearby comparison is worth making. Edinburgh is a better bet in September — within a degree on temperature, 4 days less rain. Manchester is a better bet in September — within a degree on temperature, 3 days less rain.

So: September is effectively as good as it gets here — 6 points behind July, which is inside the margin where the weather stops being the deciding factor and price starts being it.

Every month in Glasgow

See all twelve months in Glasgow, or where else to go in September.