The short answer
May-June and September-October are the sweet spot for the Mediterranean: warm, less crowded and cheaper than July-August, which is hot and packed. Northern Europe (Norway, Baltic, British Isles, Iceland) runs mainly May-September. River cruises run roughly March/April to December, with Christmas market sailings in late November and December.
At a glance
| Region | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Best months |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Western Med | Few sailings | Few sailings | Season starts | Season | Great | Warm, busy | Hot, crowded | Hot, crowded | Great | Great | Season ends | Few sailings | May-Jun, Sep-Oct |
| Eastern Med / Greek Isles | Few sailings | Few sailings | Few sailings | Season starts | Great | Hot, busy | Very hot, crowded | Very hot, crowded | Great | Good | Few sailings | Few sailings | May-Jun, Sep-Oct |
| Adriatic | No cruises | No cruises | Few sailings | Season starts | Great | Warm, busy | Hot, crowded | Hot, crowded | Great | Good | Few sailings | No cruises | May-Jun, Sep |
| Norway fjords | Northern lights (coastal) | Northern lights (coastal) | Northern lights (coastal) | Few sailings | Season | Peak, long days | Peak | Peak | Season, cooler | Few sailings | Northern lights (coastal) | Northern lights (coastal) | Jun-Aug |
| Baltic | No cruises | No cruises | No cruises | Few sailings | Season | Peak, long days | Peak | Peak | Season ends | No cruises | No cruises | No cruises | Jun-Aug |
| British Isles | No cruises | No cruises | Few sailings | Season starts | Season | Season | Peak | Peak | Season | Few sailings | No cruises | No cruises | May-Sep |
| Iceland / Arctic | No cruises | No cruises | No cruises | No cruises | Few sailings | Season | Peak | Peak | Season ends | No cruises | No cruises | No cruises | Jul-Aug |
| Atlantic / Canaries | Season (mild) | Season (mild) | Season | Repositioning | Season | Few sailings | Few sailings | Few sailings | Season | Repositioning | Season (mild) | Season (mild) | Nov-Mar |
| Rivers (Danube, Rhine, Moselle, Seine, Rhone) | No cruises | No cruises | Season starts | Tulips, high-water risk | Great | Season | Warm, busy | Low-water risk | Great | Great | Christmas markets start | Christmas markets | May, Sep-Oct; Dec for markets |
| Douro | No cruises | No cruises | Season starts | Great | Great | Hot | Very hot | Very hot | Harvest | Great | Season ends | Few sailings | Apr-May, Sep-Oct |
| Elbe | No cruises | No cruises | Few sailings | Season | Great | Season | Low-water risk | Low-water risk | Season | Season | Few sailings | Christmas markets | May-Jun, Sep |
Mediterranean heat and crowds
- Barcelona's average daily high is about 82-83 F in July and August, and about 70 F in May and 72 F in October (AEMET, 1981-2010 averages).
- Athens' average daily high is about 91 F in July and 90 F in August, versus about 78 F in May and 74 F in October (National Observatory of Athens, 1961-1990 averages). Recent summers have often been hotter than these older averages.
- Ruins like the Acropolis and Ephesus have little shade. In July and August, book early-morning tours.
- Greece's per-port cruise fee is highest June-September (EUR 20 in Santorini and Mykonos, EUR 5 in other Greek ports), which shows how peak season is defined there.
Northern Europe
- Norway, the Baltic, the British Isles and Iceland are mainly a May-September cruise season, with the best weather from June to August.
- Midnight sun: in Tromso the sun does not set from about May 20 to July 22; at the North Cape from about May 14 to July 29 (Visit Norway).
- Northern lights season in Arctic Norway is September to late March (Visit Norway). Winter 'northern lights' cruises sail the Norwegian coast in those months; sightings are never guaranteed.
- Bergen, a main fjord port, gets about 2,495 mm (98 inches) of rain a year and had more than 1 mm of rain on 171-234 days a year in 2019-2025 (Bergen city / Norwegian Meteorological Institute). Pack rain gear in any month.
River cruises
- Spring (March-May): tulip cruises in the Netherlands and Belgium, cooler weather, and some risk of high water after heavy rain or snowmelt that can stop ships from passing under bridges.
- Summer (June-August): warm, busy. Late summer drought can cause low water. In August 2026 the Rhine at Kaub fell below its 2018 record low; lines swapped ships, bused guests between ships, changed boarding cities or cancelled sailings (CruiseMapper, Aug 17, 2026).
- Fall (September-October): harvest and wine season, cooler and often good value.
- Christmas markets (late November-December): Nuremberg's Christkindlesmarkt 2026 runs Nov 27 to Dec 24 (closes 2 pm on Dec 24). Days are short and cold.
- January-February: very few European river sailings.
Your checklist
Sources & what we could not confirm · 7 sources · checked 2026-11
- AEMET (Spain's weather agency): Barcelona Airport climate normals 1981-2010
- National Observatory of Athens, monthly climate means (1961-1990)
- City of Bergen, climate figures (source: Norwegian Meteorological Institute)
- Visit Norway: Northern lights and midnight sun
- CruiseMapper: Record-low Rhine water levels disrupt river cruises (Aug 17, 2026)
- City of Nuremberg: Christkindlesmarkt 2026 information (English PDF)
- MSC Cruises: Destination fees and local charges (Greece, Venice, Iceland)
Still being confirmed
- Month-by-month 'season' labels are general patterns, not taken from one official schedule; check sailings for your dates.
- Temperature figures for Danube, Douro, Norway monthly highs and Iceland were not fetched from a national weather service; only Barcelona, Athens and Bergen annual rain were verified.
- Athens climate averages come from 1961-1990; newer averages were not fetched.