Thermopolis

Stay up to date with the latest weather conditions in Thermopolis. Below you will find current data, forecasts, and helpful weather charts.

The climate in Thermopolis, USA, is characterized as continental with four distinct seasons. Winters here are cold, with average temperatures in January and February dropping below -5°C, and minimums reaching -12°C or lower. Summers, by contrast, are warm and even hot, especially in July when the average temperature rises to 23.8°C and highs often exceed 30°C. Spring and autumn are transitional seasons with moderate temperatures, featuring a gradual warming trend in spring and a cooling trend in autumn.

One of the defining features of the weather in Thermopolis is the low level of precipitation throughout the year. Most months receive only 0-1 mm of precipitation, with a slight increase to 2 mm in April and May. Even during the "wettest" months, the number of rainy days is small—for example, about 12 in May and only 3 in July. This indicates a rather dry climate. Travelers should expect significant temperature fluctuations between seasons and generally dry weather.

Thermopolis experiences a significant annual temperature range, reflecting the changing seasons. The coldest months are January and February. In January, the average temperature is -5.9°C, with nightly lows dropping to -11.7°C and daytime highs around -0.1°C. February is slightly colder, with an average temperature of -6.5°C and an average minimum of -12.8°C. Conversely, the hottest months are July and August. July leads with an average temperature 23.8°C, with daytime highs reaching an impressive 31.8°C. August follows with a comfortable average temperature 22.2°C and daytime highs around 30.0°C.

The summer period in Thermopolis, especially from June to August, is characterized by warmth that turns into true heat. While the average temperature in June sits at 19.2°C (with highs up to 26.8°C), July and August bring higher values, often exceeding 30°C during the day. However, nights remain relatively cool: for example, the average minimum temperature in July is 15.8°C, and in August, it is 14.5°C. This creates a significant daily temperature range, which can reach 16°C in July, providing freshness after a sweltering day.

The winter months, from December to February, are quite harsh and frosty in Thermopolis. Monthly average temperatures are consistently negative: -4.5°C in December, -5.9°C in January, and -6.5°C in February. During the day, air temperatures often hover around zero or stay below that mark (for example, -0.1°C in January and February as the average high). At night, the mercury regularly drops much lower, reaching -9.9°C in December and nearly -13°C in February. The difference between daytime and nighttime temperatures in winter is also noticeable, averaging 10-12°C, which underscores the continental nature of the climate.

Thermopolis experiences a very dry climate throughout the year, with extremely low total precipitation. There is no pronounced rainy season, though there are periods with a slightly higher or lower probability of precipitation. Overall, you shouldn't expect heavy rain or snowfall in Thermopolis.

The highest number of days with precipitation occurs during the spring months. May is the month with the highest frequency of precipitation, averaging 12 wet days, followed by April with 9 days. However, even during these periods, the total amount remains minimal—around 2 mm per month. The driest months, when almost no precipitation is recorded (0 mm), are January, July, and December. July also stands out with the fewest days of precipitation—only about 3 days.

The nature of precipitation changes with the season. In the winter months (December, January, February), when average temperatures consistently stay below freezing, any precipitation falls as snow. However, the amount is very small: for example, no precipitation is recorded in January and December, while only about 1 mm falls in February. In transitional months like March and November, both rain and snow are possible. In summer (June, July, August), precipitation, if it occurs at all, consists of rare and very light showers. Generally, even in months with the highest number of "wet days," this usually means light, short-lived showers rather than prolonged rain or heavy snow.

When planning a trip to Thermopolis, it's important to consider the significant temperature fluctuations throughout the year. In winter (December–February), it is quite cold, with average temperatures dropping below freezing—sometimes as low as -12°C—so be sure to bring very warm clothing: thermal underwear, an insulated jacket, a hat, gloves, and a scarf. In summer (June–August), the weather is warm, and even hot in July, with highs reaching 31.8°C. Lightweight, breathable items like t-shirts, shorts, and sundresses are ideal for this period. Don't forget sunscreen, sunglasses, and a hat, as there is almost no rain in summer.

Spring (March–May) and autumn (September–November) are transitional seasons with a wide range of temperatures. March can still be chilly, while May is comfortably warm. September offers mild weather, but it turns cold again by November. Layering is the perfect strategy for these periods: t-shirts, long-sleeves, sweaters or fleece tops, plus a windbreaker or a light jacket. Although precipitation in Thermopolis is generally low, the number of rainy days increases in the spring months, especially in May, so a compact umbrella or a waterproof jacket might come in handy.

Regardless of the time of year, you will need comfortable walking shoes for exploring Thermopolis and its surroundings. Since overall precipitation is low, your main focus when packing should be on the temperature. Dressing in layers will allow you to easily adapt to weather changes throughout the day, especially during the shoulder seasons. Even in summer, evenings can be cool, so a light sweater or jacket won't go to waste.