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Mont-Saint-Michel sits in a tidal bay on the Normandy coast where the Atlantic Ocean meets the Couesnon river, and its weather is classic oceanic: mild, changeable, and windy all year. Daytime highs run from 9°C (48°F) in January to 22.5°C (72.5°F) in July and August, and the site receives about 725 mm (28 in) of rain spread across roughly 170 rainy days a year. The biggest weather factor here is not temperature but the tide, which can rise up to 14 metres and turn the mount into an island twice a day. This Mont-Saint-Michel weather guide breaks the year down month by month.
Mont-Saint-Michel Weather by Month: An Overview
The bay of Mont-Saint-Michel has a temperate maritime climate, coded Cfb under the Köppen system, with an annual average temperature of 11.2°C (52°F). Rain falls year-round with no dry season, peaking in November at 88 mm and bottoming out in July at 40 mm. Sunshine totals about 1,700 hours a year, most of it between May and September. Wind off the Atlantic is constant, averaging 20 to 25 km/h, and sea fog rolls in on roughly 60 mornings a year, most often in spring and autumn. For the full picture of when conditions are best, see our best time to visit Mont-Saint-Michel guide.
Mont-Saint-Michel Weather by Month: Winter (December to February)
Winter is cool and damp. December averages a high of 9.5°C (49°F) and a low of 4°C (39°F) with 85 mm of rain. January is the coldest month at 6.3°C (43°F) on average, with highs around 9°C (48°F) and lows of 3.5°C (38°F), and it brings the most rainy days at roughly 17. February stays nearly identical at a 9.5°C (49°F) high and 3.5°C (38°F) low with 58 mm of rain. Snow is rare, falling on only a handful of days each winter, but frost can glaze the causeway on clear nights, and wind chill on the exposed ramparts makes it feel several degrees colder than the thermometer reads.
Mont-Saint-Michel Weather by Month: Spring (March to May)
Spring warms steadily and is when the highest tides of the year arrive. March reaches a 12°C (54°F) high and 5°C (41°F) low with 55 mm of rain. By April, highs hit 14°C (57°F) and rain eases to 50 mm. May is the first reliably pleasant month, with 17°C (63°F) highs, 9.5°C (49°F) lows, and 52 mm of rain alongside 6.5 daily sunshine hours. The March equinox spring tides are among the year’s biggest, so you can watch the water race back in across the flats faster than a person can run.
Mont-Saint-Michel Weather by Month: Summer (June to August)
Summer is mild rather than hot, which makes it the busiest season. June averages 20°C (68°F) highs and 12°C (54°F) lows with 45 mm of rain. July and August are the warmest and driest, both averaging 22.5°C (72.5°F) highs and 14°C (57°F) lows, with 40 and 45 mm of rain respectively and up to 7 hours of daily sunshine. Heatwaves above 30°C (86°F) are rare even in August. The English Channel sea temperature peaks at just 17 to 18°C (63 to 64°F) in August, and the bay floor is mud and quicksand rather than beach sand, so this is not a swimming destination. Pack for wind even in July, and use our things to do in Mont-Saint-Michel list to plan indoor stops.
Mont-Saint-Michel Weather by Month: Autumn (September to November)
Autumn opens pleasant and ends wet. September still reaches 20°C (68°F) highs and 12.5°C (55°F) lows with 55 mm of rain, and the September equinox brings the year’s second set of extreme spring tides. October cools to a 16°C (61°F) high and rain jumps to 78 mm. November is the wettest month at 88 mm with 12°C (54°F) highs, and sea fog returns in force, sometimes hiding the mount until mid-morning. The autumn tides and quieter streets are a draw for the guided crossings covered in our Mont-Saint-Michel events and festivals calendar.
Mont-Saint-Michel Weather: Tides, Wind, and Fog
The tide defines Mont-Saint-Michel more than any temperature. The bay has a tidal range of up to 14 metres, the largest in continental Europe, and during spring tides the water advances across the sand at walking pace or faster. Always check the tide table, published by the tourism office and based on Saint-Malo timings, before stepping onto the sand, and never cross the bay without a certified guide. Wind is strongest from October to March, and fog is most common on spring and autumn mornings. Practical transport and tide safety detail is in our Mont-Saint-Michel travel tips guide, and for a sense of the different zones to stay in, see our Mont-Saint-Michel neighborhoods overview.
Mont-Saint-Michel Weather by Month: Comparison Table
| Month | Avg High | Avg Low | Rain (mm) | Sun (hrs/day) |
|---|---|---|---|---|
| January | 9°C / 48°F | 3.5°C / 38°F | 74 | 2.1 |
| February | 9.5°C / 49°F | 3.5°C / 38°F | 58 | 3.0 |
| March | 12°C / 54°F | 5°C / 41°F | 55 | 4.0 |
| April | 14°C / 57°F | 6.5°C / 44°F | 50 | 5.5 |
| May | 17°C / 63°F | 9.5°C / 49°F | 52 | 6.5 |
| June | 20°C / 68°F | 12°C / 54°F | 45 | 7.0 |
| July | 22.5°C / 72.5°F | 14°C / 57°F | 40 | 7.0 |
| August | 22.5°C / 72.5°F | 14°C / 57°F | 45 | 6.5 |
| September | 20°C / 68°F | 12.5°C / 55°F | 55 | 5.5 |
| October | 16°C / 61°F | 10°C / 50°F | 78 | 4.0 |
| November | 12°C / 54°F | 6.5°C / 44°F | 88 | 2.5 |
| December | 9.5°C / 49°F | 4°C / 39°F | 85 | 2.0 |
Monthly figures are long-term averages for the bay of Mont-Saint-Michel, close to Granville and Saint-Malo coastal records. For a full breakdown of where to sleep across the seasons, see our where to stay in Mont-Saint-Michel guide.
