Climate and Average Weather Year Round in Saint Marys United States

In Saint Marys, the summers are hot, humid, and mostly clear and the winters are very cold, snowy, windy, and partly cloudy. Over the course of the year, the temperature typically varies from 23°F to 93°F and is rarely below 9°F or above 103°F.

Based on the tourism score, the best time of year to visit Saint Marys for warm-weather activities is from mid May to late September.

The hot season lasts for 3.4 months, from June 2 to September 14, with an average daily high temperature above 83°F. The hottest month of the year in Saint Marys is July, with an average high of 92°F and low of 70°F.

The cold season lasts for 3.0 months, from November 24 to February 25, with an average daily high temperature below 52°F. The coldest month of the year in Saint Marys is January, with an average low of 24°F and high of 43°F.

In Saint Marys, the average percentage of the sky covered by clouds experiences significant seasonal variation over the course of the year.

The clearer part of the year in Saint Marys begins around June 6 and lasts for 5.0 months, ending around November 6.

The clearest month of the year in Saint Marys is July, during which on average the sky is clear, mostly clear, or partly cloudy 72% of the time.

The cloudier part of the year begins around November 6 and lasts for 7.0 months, ending around June 6.

The cloudiest month of the year in Saint Marys is February, during which on average the sky is overcast or mostly cloudy 46% of the time.

A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days in Saint Marys varies significantly throughout the year.

The wetter season lasts 5.6 months, from April 7 to September 25, with a greater than 23% chance of a given day being a wet day. The month with the most wet days in Saint Marys is June, with an average of 11.2 days with at least 0.04 inches of precipitation.

The drier season lasts 6.4 months, from September 25 to April 7. The month with the fewest wet days in Saint Marys is January, with an average of 2.2 days with at least 0.04 inches of precipitation.

Among wet days, we distinguish between those that experience rain alone, snow alone, or a mixture of the two. Based on this categorization, the most common form of precipitation in Saint Marys changes throughout the year.

Rain alone is the most common for 11 months, from January 22 to December 28. The month with the most days of rain alone in Saint Marys is June, with an average of 11.2 days.

Snow alone is the most common for 3.6 weeks, from December 28 to January 22. The month with the most days of snow alone in Saint Marys is January, with an average of 0.9 days.

Rainfall

To show variation within the months and not just the monthly totals, we show the rainfall accumulated over a sliding 31-day period centered around each day of the year. Saint Marys experiences extreme seasonal variation in monthly rainfall.

Rain falls throughout the year in Saint Marys. The month with the most rain in Saint Marys is June, with an average rainfall of 4.2 inches.

The month with the least rain in Saint Marys is January, with an average rainfall of 0.3 inches.

Snowfall

As with rainfall, we consider the snowfall accumulated over a sliding 31-day period centered around each day of the year. Saint Marys experiences some seasonal variation in monthly snowfall.

The snowy period of the year lasts for 4.3 months, from November 19 to March 28, with a sliding 31-day snowfall of at least 1.0 inches. The month with the most snow in Saint Marys is January, with an average snowfall of 2.6 inches.

The snowless period of the year lasts for 7.7 months, from March 28 to November 19. The least snow falls around July 22, with an average total accumulation of 0.0 inches.

The length of the day in Saint Marys varies significantly over the course of the year. In 2024, the shortest day is December 21, with 9 hours, 33 minutes of daylight; the longest day is June 20, with 14 hours, 47 minutes of daylight.

The earliest sunrise is at 6:08 AM on June 12, and the latest sunrise is 1 hour, 49 minutes later at 7:57 AM on November 2. The earliest sunset is at 5:11 PM on December 5, and the latest sunset is 3 hours, 45 minutes later at 8:56 PM on June 27.

Daylight saving time (DST) is observed in Saint Marys during 2024, starting in the spring on March 10, lasting 7.8 months, and ending in the fall on November 3.

The figure below presents a compact representation of key lunar data for 2024. The horizontal axis is the day, the vertical axis is the hour of the day, and the colored areas indicate when the moon is above the horizon. The vertical gray bars (new Moons) and blue bars (full Moons) indicate key Moon phases.

We base the humidity comfort level on the dew point, as it determines whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid. Unlike temperature, which typically varies significantly between night and day, dew point tends to change more slowly, so while the temperature may drop at night, a muggy day is typically followed by a muggy night.

Saint Marys experiences extreme seasonal variation in the perceived humidity.

The muggier period of the year lasts for 3.9 months, from May 23 to September 20, during which time the comfort level is muggy, oppressive, or miserable at least 14% of the time. The month with the most muggy days in Saint Marys is July, with 16.6 days that are muggy or worse.

The least muggy day of the year is January 31, when muggy conditions are essentially unheard of.

This section discusses the wide-area hourly average wind vector (speed and direction) at 10 meters above the ground. The wind experienced at any given location is highly dependent on local topography and other factors, and instantaneous wind speed and direction vary more widely than hourly averages.

The average hourly wind speed in Saint Marys experiences significant seasonal variation over the course of the year.

The windier part of the year lasts for 3.2 months, from February 18 to May 25, with average wind speeds of more than 11.3 miles per hour. The windiest month of the year in Saint Marys is April, with an average hourly wind speed of 12.6 miles per hour.

The calmer time of year lasts for 8.8 months, from May 25 to February 18. The calmest month of the year in Saint Marys is August, with an average hourly wind speed of 9.9 miles per hour.

The predominant average hourly wind direction in Saint Marys varies throughout the year.

The wind is most often from the south for 8.7 months, from March 10 to November 30, with a peak percentage of 66% on July 4. The wind is most often from the north for 3.4 months, from November 30 to March 10, with a peak percentage of 40% on January 1.

To characterize how pleasant the weather is in Saint Marys throughout the year, we compute two travel scores.

The tourism score favors clear, rainless days with perceived temperatures between 65°F and 80°F. Based on this score, the best time of year to visit Saint Marys for general outdoor tourist activities is from mid May to late September, with a peak score in the first week of September.

The beach/pool score favors clear, rainless days with perceived temperatures between 75°F and 90°F. Based on this score, the best time of year to visit Saint Marys for hot-weather activities is from mid June to late August, with a peak score in the third week of July.

Methodology

For each hour between 8:00 AM and 9:00 PM of each day in the analysis period (1980 to 2016), independent scores are computed for perceived temperature, cloud cover, and total precipitation. Those scores are combined into a single hourly composite score, which is then aggregated into days, averaged over all the years in the analysis period, and smoothed.

Our cloud cover score is 10 for fully clear skies, falling linearly to 9 for mostly clear skies, and to 1 for fully overcast skies.

Our precipitation score, which is based on the three-hour precipitation centered on the hour in question, is 10 for no precipitation, falling linearly to 9 for trace precipitation, and to 0 for 0.04 inches of precipitation or more.

Our tourism temperature score is 0 for perceived temperatures below 50°F, rising linearly to 9 for 65°F, to 10 for 75°F, falling linearly to 9 for 80°F, and to 1 for 90°F or hotter.

Our beach/pool temperature score is 0 for perceived temperatures below 65°F, rising linearly to 9 for 75°F, to 10 for 82°F, falling linearly to 9 for 90°F, and to 1 for 100°F or hotter.

Definitions of the growing season vary throughout the world, but for the purposes of this report, we define it as the longest continuous period of non-freezing temperatures (≥ 32°F) in the year (the calendar year in the Northern Hemisphere, or from July 1 until June 30 in the Southern Hemisphere).

The growing season in Saint Marys typically lasts for 6.8 months (208 days), from around April 4 to around October 29, rarely starting before March 17 or after April 21, and rarely ending before October 10 or after November 16.

Growing degree days are a measure of yearly heat accumulation used to predict plant and animal development, and defined as the integral of warmth above a base temperature, discarding any excess above a maximum temperature. In this report, we use a base of 50°F and a cap of 86°F.

Based on growing degree days alone, the first spring blooms in Saint Marys should appear around March 13, only rarely appearing before February 28 or after April 4.

This section discusses the total daily incident shortwave solar energy reaching the surface of the ground over a wide area, taking full account of seasonal variations in the length of the day, the elevation of the Sun above the horizon, and absorption by clouds and other atmospheric constituents. Shortwave radiation includes visible light and ultraviolet radiation.

The average daily incident shortwave solar energy experiences significant seasonal variation over the course of the year.

The brighter period of the year lasts for 3.9 months, from April 23 to August 20, with an average daily incident shortwave energy per square meter above 6.3 kWh. The brightest month of the year in Saint Marys is July, with an average of 7.1 kWh.

The darker period of the year lasts for 3.1 months, from November 5 to February 8, with an average daily incident shortwave energy per square meter below 3.4 kWh. The darkest month of the year in Saint Marys is December, with an average of 2.5 kWh.

For the purposes of this report, the geographical coordinates of Saint Marys are 37.707 deg latitude, -97.640 deg longitude, and 1,509 ft elevation.

The topography within 2 miles of Saint Marys is essentially flat, with a maximum elevation change of 85 feet and an average elevation above sea level of 1,486 feet. Within 10 miles is essentially flat (276 feet). Within 50 miles contains only modest variations in elevation (833 feet).

The area within 2 miles of Saint Marys is covered by cropland (90%) and grassland (10%), within 10 miles by cropland (71%) and grassland (24%), and within 50 miles by cropland (57%) and grassland (40%).