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Mainz sits in the Upper Rhine Valley at the mouth of the River Main, about 40 km (25 miles) southwest of Frankfurt. The valley position gives the city one of Germany’s warmest, driest climates, with about 610 mm of rain and 1,600 hours of sunshine a year. Use this Mainz weather by month breakdown to plan what to pack and when to book. For the full picture of the city, start with our Mainz travel guide.
Mainz Weather by Month: Winter (December to February)
Winters in Mainz are cool but rarely severe because the Rhine Valley runs 2 to 3 degrees Celsius warmer than the surrounding high ground. January is the coldest month, averaging 4 C (39 F) by day and 0 C (32 F) at night, with 42 mm of rain across about 11 days. December averages a high of 5 C and a low of 1 C with 52 mm of rain, and February is nearly identical at 6 C high and 0 C low. Snow falls most winters but usually settles for only a few days before melting. Pack a waterproof coat, gloves, and layers, and keep an eye on the Mainz events and festivals calendar, since Carnival and the Christmas markets run through this stretch.
Mainz Weather by Month: Spring (March to May)
Spring warms up quickly. March averages 11 C (52 F) by day and 3 C at night with 41 mm of rain, then April climbs to 16 C (61 F) high and 6 C low with 44 mm. May is the first reliably pleasant month, averaging 20 C (68 F) high and 10 C (50 F) low with 60 mm of rain. Sunshine jumps from about 120 hours in March to 205 hours in May, which makes late spring a strong candidate if you are weighing the best time to visit Mainz.
Mainz Weather by Month: Summer (June to August)
Summers are warm and the driest-per-sunshine part of the year. July is the warmest month at 25 C (77 F) high and 15 C (59 F) low, with 66 mm of rain, and August is the same temperature with slightly less rain at 58 mm. Heatwaves can push daytime highs above 33 C (91 F) for short runs, and the valley holds humidity, so afternoon thunderstorms are common in June and July. Expect about 210 to 220 sunshine hours in June and July, the best stretch for the outdoor cafes and Rhine promenades listed in our things to do in Mainz guide.
Mainz Weather by Month: Autumn (September to November)
Autumn is mild and often dry early on. September averages 21 C (70 F) high and 11 C (52 F) low with 51 mm of rain, before October drops to 15 C (59 F) high and 7 C low with 46 mm. November cools sharply to 9 C (48 F) high and 3 C low with 48 mm, and fog can settle over the Rhine in the mornings. The wine harvest fills the streets around late August and September, which ties in well with the neighborhoods around the old town covered in our Mainz neighborhoods guide.
Mainz Weather by Month: Climate Data Table
| Month | Avg High (C) | Avg Low (C) | Rain (mm) | Sunshine (hrs) |
|---|---|---|---|---|
| January | 4 | 0 | 42 | 45 |
| February | 6 | 0 | 38 | 75 |
| March | 11 | 3 | 41 | 120 |
| April | 16 | 6 | 44 | 175 |
| May | 20 | 10 | 60 | 205 |
| June | 23 | 13 | 64 | 210 |
| July | 25 | 15 | 66 | 220 |
| August | 25 | 14 | 58 | 205 |
| September | 21 | 11 | 51 | 155 |
| October | 15 | 7 | 46 | 100 |
| November | 9 | 3 | 48 | 55 |
| December | 5 | 1 | 52 | 40 |
These figures come from long-term averages for the Mainz area and vary by a degree or two from year to year. If you want hotel prices matched to each season rather than the weather alone, see our where to stay in Mainz guide, and for getting to the city, the Mainz travel tips page covers Frankfurt Airport transfers.
