Weather in Boise

Planning a trip or simply want to know what the weather is like right now in Boise? Here you will find the freshest information on weather conditions, as well as detailed forecasts and useful charts.

Boise, located in the USA, possesses a continental climate with four distinct seasons. This means the city experiences significant temperature contrasts throughout the year. In general, the climate can be characterised as quite dry, especially in the summer months, with a low overall level of precipitation.

Summer in Boise is typically hot and sunny, with average temperatures in July reaching 25.4°C, and maximum values often exceeding 30°C. Notably, the summer months, especially July, are characterised by minimal rainfall – just 0 mm and 0 rainy days. Winters are cold, with average temperatures around zero degrees Celsius (for example, 0.1°C in January) and periodic precipitation, most often in the form of snow, although in small amounts (about 2 mm per month). Spring and autumn are pleasant transitional seasons with moderate temperatures, preparing you for the summer heat or winter chill.

The temperature regime in Boise is characterised by distinct seasonal contrasts. The annual temperature course shows significant fluctuations: from frosty winter days to hot summer ones. The hottest period is usually July, when the average temperature reaches 25.4°C, and maximum daily values often rise to 33.6°C. It is followed by August with an average temperature of 24.2°C and highs up to 32.2°C. Conversely, the coldest months are recognised as December and January, where the monthly average temperature hovers around -0.1°C and 0.1°C respectively, and minimum night temperatures can drop to -3.8°C.

Summer in Boise brings predominantly hot and dry weather. Starting from June, when the average maximum temperature is about 27.0°C, the thermometer steadily climbs, reaching a peak in July. A characteristic feature of the summer months is the significant difference between day and night temperatures. For instance, in July with a daytime high of 33.6°C, the night temperature can drop to 17.1°C, providing pleasant coolness after the daytime heat. This makes evenings and early morning hours particularly comfortable.

The winter period in Boise is distinguished by cool, and at times frosty, weather. From December to February, average daytime temperatures range from 3.6°C to 5.7°C; however, nights regularly bring sub-zero temperatures, with minimum values reaching -3.8°C in December and January, and -3.5°C in February. Diurnal temperature fluctuations in winter are less pronounced than in summer, but the difference between daytime warmth and nocturnal cold is still palpable. The transitional seasons – spring and autumn – offer more moderate temperatures, gradually preparing for the shift in seasonal extremes.

Boise is characterised by a rather low level of precipitation throughout the year, however, there is a clear division into wetter and drier seasons. Overall, the city is not known for torrential rains, and even in the "wettest" months, the amount of precipitation remains moderate, usually not exceeding 2 mm per month.

The greatest amount of precipitation and days with it occurs in the period from late autumn to early spring. January and December are the wettest months in terms of precipitation frequency, counting 12 days with it each. Given that average temperatures in these months hover around zero degrees Celsius (0.1°C in January, -0.1°C in December), precipitation during this period, as well as in February (11 days with precipitation), most often falls in the form of light snow. November (10 days) and March (11 days) also demonstrate an increased probability of precipitation, which can be either rain or snow.

Summer months in Boise, on the contrary, are exceptionally dry. July stands out as an absolutely dry month, when on average neither precipitation (0 mm) nor days with it are registered. August and September are also very arid: just 0 mm of precipitation and respectively 2 and 3 days when it might fall. Even in transitional months, such as June and October, the amount of rainfall is minimal (1 mm and 4-5 days with precipitation), which underscores the general aridity of the climate, especially during the warm time of the year.

When packing your suitcase for a trip to Boise, it is important to consider its continental climate with distinct seasons and significant temperature fluctuations, especially between day and night. In summer (June-September), it is hot and very dry here. You will need light, breathable clothing made of natural fabrics, shorts, t-shirts, and sandals. Do not forget sunscreen with high SPF, sunglasses, and a hat, as the sun can be very active. Despite the daytime heat, evenings can be cool (a difference of up to 15-16°C), so a light jacket or jumper will be very handy. Given the almost complete absence of rainfall in July and August, you are unlikely to need an umbrella.

In winter (December-February), it is cold in Boise; average temperatures hover around zero, and nights see frosts down to -3.8°C. Be sure to take warm layered clothing: thermal underwear, fleece jackets, jumpers, a warm winter coat (preferably windproof), a hat, gloves, and a scarf. Although the amount of precipitation is small (about 2 mm per month), it often falls as snow, so waterproof footwear with good tread will be useful. For the shoulder seasons (March-May, October-November), the principle of layering is characteristic. During the day it can be pleasantly warm, especially in May (up to +21°C) or October (up to +17°C), but mornings and evenings are cool. A light jacket, jumper, jeans or thick trousers, as well as closed comfortable shoes, will be the optimal choice. During these periods, light precipitation is possible, so a compact umbrella or a light waterproof jacket may come in handy, especially in November and March.

Regardless of the season, comfortable walking shoes are a must-have, as there is much to see on foot in Boise. Given the generally dry climate, moisturising cream for the skin and lip balm may also prove useful, especially in winter and the dry summer months. The principle of layering clothing is your best friend in Boise, allowing you to easily adapt to temperatures changing throughout the day.