The average temperature for the week of 30 June 2025 - 6 July 2025 was 23 °C (73 °F) during the day and 8 °C (46 °F) during the night. Both the daily and night temperatures in Keystone are slightly above the long-term average, which is around 21 °C (70 °F) and 3 °C (37 °F) respectively. Friday marked the coldest day of the week. The average temperatures observed during different times of day (based on local time) were as below: 7am 12 °C (54 °F), 10am 19 °C (66 °F), 1pm 22 °C (72 °F), 4pm 21 °C (70 °F), 7pm 18 °C (64 °F), 10pm 12 °C (54 °F).

During this week: 4 days without rain and 3 days with light rain were observed. During the whole week, total of 5 mm (0.20 in) of precipitation was observed, which is below the long term average for Keystone, which is 11 mm (0.43 in). From dawn to dusk, there was an average of 59 % cloud coverage during the day.

Average speed of wind was 2.4 m/s. The atmosferic pressure ranged from 1005 hpa to 1027 hpa. On average, the air humidity in Keystone was 47 %.

During the daytime (from dawn to dusk), there were in average: 5.5 hours clear skies, 2.5 hours partially overcast skies, 8 hours overcast skies and 0.5 hours rainy weather. On average, the time of sunrise was 05:41, and the time of sunset was 20:34.

Weather overview

In Keystone, situated within the borders of the United States of America, residents and visitors alike enjoy a temperate continental climate. Here, the variation in diurnal temperatures is quite notable, with daytime highs fluctuating between 0 °C (32 °F) in the chilly month of December and reaching 22 °C (72 °F) during the warmest month of July. Keystone experiences its driest conditions in October, showcasing a mere 8 days with precipitation, while August proves to be the most saturated, with rain falling over 13 days of the month. The warmest nocturnal temperatures peak in July at 5 °C (40 °F), whereas the chilliest nights in January see temperatures plummeting to -15 °C (5 °F).

January weather

As January ushers in, Keystone experiences its coldest night temperatures, which drop to -15 °C (5 °F). Concurrently, the duration of sunshine without clouds begins to incrementally increase, shown by 7 hours of clear sun.

February weather

February marks the onset of increased precipitation, tallying a total of 10 days of rain in Keystone. Meanwhile, a gentle rise in daytime temperatures can be seen, warming up to 1 °C (34 °F), paralleled by a slight increase in sunny hours, amounting to 8 hours.

March weather

March brings a continued uptrend in daytime warmth, showing 4 °C (39 °F) in Keystone. Along with increasing night temperatures, which hit -11 °C (11 °F), the initial surge in rainfall is observed with 44 mm (1.74 in), while rainy days are moreover on the rise, documented at 12 days. Concomitantly, sunny hours persist in their upward trajectory, now at 8 hours.

April weather

In Keystone, April's showers bring a further elevation in rainfall metrics, accumulating 49 mm (1.94 in). Correspondingly, daytime warmth progresses to 7 °C (45 °F), while the nocturnal warmth follows suit, rising to -8 °C (18 °F). The zenith of wind velocities is recorded this month. Sunshine hours maintain their ascension, hitting 9 hours, as the nadir of humidity levels becomes apparent.

May weather

A steady increase in night temperatures to -2 °C (28 °F) is observed in Keystone during May, with day temperatures also climbing, now registered at 13 °C (56 °F).

June weather

The advent of June signals the upcoming tourist season in Keystone, with the day temperature reaching a comfortable 19 °C (66 °F), and the night temperature exhibiting a positive trend as well, resting at 1 °C (35 °F). A decline in rainfall volume marks the beginning of drier periods, documented at 39 mm (1.54 in), while the number of rainy days also starts to taper off, showing 10 days. The apex of cloudless sunshine hours can be experienced.

July weather

During July, Keystone reaches its peak daytime temperatures at 22 °C (72 °F), with nocturnal temperatures hitting seasonal heights as well. Concurrently, there's a noticeable increase in the number of days with rain, registering at 13 days, and an inception of heightened rainfall is seen. The spread of sunny hours begins to recede during this stretch.

August weather

In Keystone, the waning of summertime warmth becomes evident with a day temperature dip to 21 °C (70 °F), coupled with an initial decrease in night temperatures as well. The acme of monthly precipitation and rainy days is observed, reaching 13 days and 58 mm (2.30 in) respectively. The diminution of sunlit hours continues its trend, now noted at 9 hours. Wind speeds culminate in their annual low this month.

September weather

As Keystone transitions into September, a similarity in temperature descents is apparent, with day figures showing 17 °C (63 °F) and night figures at 0 °C (32 °F). The commencement of lesser rainy days emerges, indicated by 10 days, along with a slight reduction in rainfall, recorded at 41 mm (1.60 in). A continuous diminishment in hours of sunlight is visible, settling at 8 hours.

October weather

October in Keystone observes the fewest rainy days annually, counting 8 days, and a parallel descent in rainfall accumulation, which records a minimal 33 mm (1.31 in). The overall cooling pattern continues for daytime and nocturnal temperatures, now reading -5 °C (23 °F).

November weather

With the advent of November in Keystone, an increment in the number of rainy days becomes apparent, totaling 9 days. A persistent decline in night temperatures is observed, dropping to -10 °C (14 °F), while day temperatures also drift downward, marginally, to 4 °C (39 °F). The waning hours of sunlight persist, notching 6 hours.

December weather

Keystone's night temperatures continue their downward spiral in December, bottoming out at -14 °C (6 °F), while the nadir of daytime temperatures is witnessed, with the thermometer barely climbing to 0 °C (32 °F). The relative humidity achieves its maximum, peaking at 56 %. A paucity in sunny hours becomes the norm, now framed at 6 hours, and the shortest duration of daylight is recorded.

What is the coldest night temperature in Keystone during January and how much sunshine can we expect?

In January, Keystone's chilliest night can plummet to -15 °C (5 °F), and you can anticipate around 7 hours of unobstructed sunlight.

How do the number of rainy days and day temperatures in Keystone compare as we move into February?

February in Keystone sees a rise in both rainy days, with a count of 10 days, and day temperatures, reaching up to 1 °C (34 °F).

As March arrives, how does the temperature range vary and what changes are noted in Keystone's precipitation levels?

In March, Keystone experiences a daytime temperature uptick to 4 °C (39 °F) and a slight night temperature increase to -11 °C (11 °F). Rainfall also intensifies to 44 mm (1.74 in), marking a continued increment in the number of rainy days to 12 days.

What are the main climatic changes observed during April in Keystone?

April in Keystone is characterized by rising day and night temperatures of 7 °C (45 °F) and -8 °C (18 °F) respectively, increasing precipitation with 49 mm (1.94 in), and the peak wind speeds for the year.

How does the night temperature shift in Keystone as we transition into May?

During May, Keystone nights grow warmer, with temperatures ascending to -2 °C (28 °F).

With the onset of Keystone's tourist season in June, how do the day and night temperatures as well as rainfall patterns behave?

In June, with the tourist season approaching, Keystone enjoys increasing day and night temperatures of 19 °C (66 °F) and 1 °C (35 °F) respectively, alongside a decrease in both rainfall volume to 39 mm (1.54 in) and the number of rainy days.

How does the summer weather in Keystone peak with regards to temperature and rainfall in July?

Keystone's summertime peaks in July with the highest day and night temperatures of the year at 22 °C (72 °F), accompanied by an uptick in rainy days numbered at 13 days.

How is the decline of summer in Keystone marked by changes in temperatures and precipitation during August?

August in Keystone showcases a notable decline in day temperatures to 21 °C (70 °F) while also witnessing the annual peak in precipitation and number of rainy days.

What weather changes can be expected with the arrival of September in Keystone?

September in Keystone brings a cooling trend with day temperatures retreating to 17 °C (63 °F), and a subtle decrease in both rainfall and the occurrence of rainy days.

How do rainy days and temperatures in Keystone adjust during October?

October in Keystone features the minimum number of rainy days, at just 8 days, alongside a continued reduction in both day and night temperatures.

What shifts in climate patterns are notable in Keystone during November?

November in Keystone is characterized by an uptick in rainy days to 9 days and a steady drop in temperatures and sunlight exposure as winter approaches.

How do the cold and daylight hours shift during December in Keystone?

December in Keystone marks the coldest night temperatures and shortest daylight hours of the year, along with a peak in relative humidity.