The short answer
If swimming matters most: July to early September. If you want long, bright days at pleasant temperatures without the crowds: late May to late June. If quiet, price and clear air are the priority: September and October. And if you like storms, empty beaches and saunas: January and February – there are people who do, and we are among them.
Grömitz climate table: all twelve months
| Month | Sea | Air max | Air min | Sun/day | Rain days |
|---|---|---|---|---|---|
| January | 3 °C | 3 °C | −2 °C | 2 h | 11 |
| February | 2 °C | 4 °C | −1 °C | 2 h | 8 |
| March | 3 °C | 8 °C | 1 °C | 3 h | 8 |
| April | 6 °C | 14 °C | 5 °C | 5 h | 7 |
| May | 11 °C | 18 °C | 9 °C | 6 h | 8 |
| June | 16 °C | 21 °C | 12 °C | 7 h | 10 |
| July | 18 °C | 23 °C | 15 °C | 8 h | 10 |
| August | 19 °C | 23 °C | 15 °C | 7 h | 10 |
| September | 16 °C | 19 °C | 12 °C | 5 h | 8 |
| October | 13 °C | 13 °C | 8 °C | 3 h | 9 |
| November | 9 °C | 8 °C | 3 °C | 2 h | 9 |
| December | 5 °C | 4 °C | 0 °C | 1 h | 11 |
The annual mean sea temperature is about 10 °C. Note the lag: in September the water is still 16 °C – as warm as June – while the air is already four degrees cooler. That is the main reason September is so popular with repeat guests here.
When can you swim in Grömitz?
As a rough rule: from 16 °C most guests go in without hesitating, and from 18 °C it feels comfortable to most people. Which gives:
- June to September – the swimming season proper (16 to 19 °C)
- May and October – for the hardy and for quick dips (11 to 13 °C)
- November to April – winter bathing, which has a real following in Grömitz
One caveat: the Baltic responds faster than an ocean. Several days of offshore easterly wind can push the warm surface layer away and draw cooler water in – a 19-degree August can briefly sit at 15. Two calm days and it is back.
Month by month: what to expect
January and February are quiet. The beach is yours, the Grömitzer Welle pool and the saunas are running, and events such as the February beach fire punctuate the month. Cold, often grey – but a clear frosty day over the bay is spectacular.
March and April bring the first long walks. From April sunshine rises sharply to five hours a day, and the Easter holidays fill the resort for a fortnight.
May is one of the underrated months: 18 °C, six hours of sun, everything open, but not yet busy. The best time of year for cycling and walking.
June has the longest days – in mid-June it does not go properly dark until around 10pm. The water is 16 °C and the German school holidays have not started.
July and August are peak season: warmest water, full beach sections, the complete events programme including Sonne, Strand & Sterne in early July and Ostsee in Flammen in August.
September is our own favourite: 16 °C water, 19 °C air, quiet beaches, good light. The shoulder season starts on 5 September, so prices drop too.
October means storm walks, amber hunting and the Lichtermeer light festival at the end of the month. November and December are the quietest weeks, apart from Christmas, which counts as high season again.
Which month suits which trip?
| You want … | Best months | Why |
|---|---|---|
| Swimming and beach days | July, August | 18–19 °C water, 23 °C air |
| Warm water without crowds | September | 16 °C water, shoulder-season rates |
| Cycling and walking | May, June, September | Mild, sunny, less wind |
| Family holiday with school-age children | July, August | Full programme, lifeguards on duty |
| Quiet and good value | March, April, October, November | Low season, €99 per night |
| Wellness and storms | January, February | Empty beach, saunas, clear air |
Season and price: the off-season effect
With us – as with most hosts in Grömitz – the nightly rate follows the season directly. For 2026 at Lieblingsplatz:
| Season | Period | Per night |
|---|---|---|
| Low | 4 Jan – 28 Mar and 31 Oct – 19 Dec | €99 |
| Shoulder | 28 Mar – 27 Jun and 5 Sep – 31 Oct | €138 |
| High | 27 Jun – 5 Sep and 19 Dec – 3 Jan | €158 |
Plus €110 for final cleaning including utilities, and the ostseecard. A week in September therefore costs about €60 a night less than the same week in mid-August – at 16 °C water instead of 19 °C.
Four Baltic weather rules that actually help
- The southern aspect is your friend. Grömitz faces south across the Bay of Lübeck, so in the prevailing westerlies and north-westerlies the resort sits in the lee of the land.
- Easterly wind cools the water. Two or three days of firm easterly can knock several degrees off the sea temperature.
- Rain days are rarely rainy days. The ten statistical rain days in July usually mean 20-minute showers, not all-day rain. For the exceptions there are indoor plans.
- Evenings are cooler than the day suggests. Temperatures drop quickly by the water after sunset. A light jacket belongs in every summer day-pack.