Half Moon Bay

Stay up to date with the latest weather conditions in Half Moon Bay. Below you will find current data, forecasts, and useful weather charts to help you plan your day.

The climate in Half Moon Bay can be described as mild and temperate throughout the year. The city does not experience sudden temperature swings, making it comfortable to visit at any time. Average annual temperatures fluctuate within a pleasant range, creating favorable conditions for outdoor activities and exploring local beauty.

Half Moon Bay has two distinct main seasons. Summer, which lasts roughly from June to September, features warm and very dry weather. Average temperatures during this period range from 15.9°C to 18.1°C, and rainfall is minimal, often reaching zero. Winter, from November to March, brings cooler and wetter weather. Average temperatures in the winter months are around 11-11.5°C, which is when the bulk of the precipitation occurs. The spring and autumn months are transitional, with moderate temperatures and a gradual change in the number of rainy days.

Half Moon Bay experiences a mild climate with moderate temperature fluctuations throughout the year. The warmest month is usually September, when the average temperature reaches 18.1°C and daily highs can rise to 21.7°C. The coolest month is considered to be February, with an average temperature of about 11.0°C and minimum night temperatures dropping to an average of 7.9°C. Overall, the annual temperature range is not very wide, making the city's weather quite comfortable for visiting any time of year.

The summer months in Half Moon Bay, especially from June to September, are characterized by pleasant warmth. Average daytime temperatures during this period fluctuate from 15.9°C in June to 18.1°C in September. Maximum temperatures rarely exceed 22°C, creating comfortable conditions without stifling heat. Daily temperature fluctuations are more noticeable in summer than in winter; the difference between daytime highs (19.4°C - 21.7°C) and nighttime lows (12.4°C - 14.4°C) can be around 7-7.5°C, especially from July to October. Nights remain pleasantly cool.

Winter in Half Moon Bay is mild and cool, without severe frosts. From December to March, average temperatures stay in the 11.0°C to 11.5°C range. Minimum night temperatures in the coldest months, January and February, drop to 7.9°C - 8.8°C, while daytime highs are usually within 13.9°C - 14.2°C. The difference between daytime and nighttime temperatures in winter is less pronounced compared to summer, at about 5-6°C. This provides relatively stable cool conditions without sharp temperature drops.

Half Moon Bay sees a distinct division of the year into wet and dry seasons. Most precipitation falls during the winter and early spring months, while summer is characterized by dry weather.

The wettest period is between December and March. December stands out as the month with the most precipitation, averaging 4 mm, and about 10 rainy days. January and March are also quite wet, with around 3 mm of precipitation and 11-13 rainy days respectively. February sees a similar amount of precipitation (3 mm), but with slightly fewer rainy days—around 7. Given the region's mild temperatures, precipitation falls mainly as rain.

The summer months—June, July, and August—are the driest in Half Moon Bay. During this period, there is virtually no rainfall (0 mm), and the number of rainy days approaches zero. September also remains very dry, with minimal precipitation and only one day when rainfall is possible. Transitional months, such as April, May, and October, are characterized by a small amount of rainfall, usually around 1 mm, and a low number of rainy days (from 1 to 4).

When planning a trip to Half Moon Bay, it is important to consider its coastal climate with moderate temperatures year-round, but noticeable seasonal variations in rainfall and how the weather feels due to potential winds. The key principle for packing should be layering. Regardless of the season, comfortable walking shoes for the coast and town will be your best friend. You should also bring a light sweater or fleece, as even on warm days, evenings can be cool, especially by the ocean.

During the winter months (roughly December to March), when the average temperature stays around 11°C and rainy days increase, you will need warmer clothes. We recommend bringing a waterproof jacket or raincoat, as well as an umbrella. Waterproof shoes will also come in handy. While it does not get freezing here, a few warm sweaters, jeans, or thick trousers will help you stay comfortable. In spring and autumn, the weather is changeable: warm sunny days can give way to cool and windy ones, making the layering principle especially relevant. A light jacket, cardigan, and scarf will not go amiss.

The summer months (June to September) in Half Moon Bay are the warmest and driest, with average temperatures around 16-18°C and highs reaching 20-22°C. During this time, light T-shirts, shorts, dresses, and sandals will be useful. However, even in summer, do not forget a light jacket or hoodie for evening walks or in case of windy weather. Sunscreen is a must, as the coastal sun can be deceptive. A hat will also help protect you from the sun on clear days.