Weather in Frankfurt am Main in September
Germany · 20-year averages, September
Prime time. If you get to pick your dates, September is the one. Highs average 22.1 °C, lows 10.4 °C, and rain falls on 9 days — nothing in the month is working against you.
September is the highest-scoring month of the twelve. The nearest rival is June, and the month at the other end of the year is December.
Rain on 9 days, 1 of them heavy. Enough to need a plan B, not enough to need a plan around it. Nothing specialised needed — this is the month you pack for the trip rather than for the weather.
What the averages hide
The averages here are honest — no hidden extremes worth planning around. Across the twenty years measured, the hottest September day reached 33.5 °C and the coldest night fell to 2.8 °C.
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 87 mm against 22 mm in the driest. In a month this wet, even a tame spread is a lot of rain in absolute terms — the 46 mm average is a reasonable planning figure, not a promise.
Wind is light at 7.6 km/h, so the temperature on the page is close to the temperature on your skin, and humidity is unremarkable at 69%.
How September sits in the year
The month is on the way down: 4.5 °C cooler than August, with October dropping another 6 °C. The first week and the last are not the same trip.
Daylight in September
12.7 hours of daylight, losing 1.8 hours across the month. That is between Frankfurt am Main's extremes of 16.4 and 8.1 hours, so days are long enough not to constrain the plan.
An inland climate
With no coast nearby, the year swings a fair way — 29 °C between the warmest afternoons and the coldest nights, wider than any coastal city at this latitude would manage.
How busy it gets
Peak season. Expect the highest prices of the year and to be booking well ahead.
Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.
September in Frankfurt am Main versus nearby
If Frankfurt am Main is one option among several, the nearby comparison is worth making. Stuttgart is close enough to be a coin toss — within a degree on temperature, 1 day more rain. Köln is close enough to be a coin toss — within a degree on temperature, 2 days more rain.
So: September is the answer for Frankfurt am Main. If it is booked out or priced out, June is the next best thing at 5 points behind, and December is the month to keep off the shortlist.
Every month in Frankfurt am Main
| Month | High °C | Low °C | Rain days | Rain mm | Humidity % | Daylight h | Score |
|---|---|---|---|---|---|---|---|
| January | 3.9 | -2 | 12 | 57 | 93 | 8.5 | 26 |
| February | 5.8 | -1.5 | 11 | 46 | 89 | 10.1 | 33 |
| March | 10.5 | 0.9 | 10 | 47 | 83 | 11.8 | 52 |
| April | 15.9 | 4.5 | 9 | 41 | 76 | 13.7 | 71 |
| May | 20 | 8.9 | 12 | 71 | 73 | 15.4 | 78 |
| June | 24.4 | 12.8 | 12 | 59 | 67 | 16.4 | 79 |
| July | 27 | 15 | 13 | 66 | 61 | 16 | 78 |
| August | 26.6 | 14.7 | 13 | 64 | 63 | 14.6 | 78 |
| September | 22.1 | 10.4 | 9 | 46 | 69 | 12.7 | 84 |
| October | 16.1 | 6.4 | 11 | 54 | 82 | 10.9 | 69 |
| November | 9.3 | 2.6 | 11 | 56 | 91 | 9.1 | 47 |
| December | 4.6 | -0.8 | 14 | 64 | 93 | 8.1 | 26 |
See all twelve months in Frankfurt am Main, or where else to go in September.
Planning the rest of the trip
- Flight time to Frankfurt am Main how long you are actually in the air
- Frankfurt am Main time zone and the difference from home
- Days until your trip count down to the departure date