Climate and Average Weather Year Round in Saint Joseph Missouri, United States

In Saint Joseph, the summers are warm, humid, and wet; the winters are short, freezing, snowy, and windy; and it is partly cloudy year round. Over the course of the year, the temperature typically varies from 19°F to 88°F and is rarely below 1°F or above 97°F.

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

The hot season lasts for 3.8 months, from May 25 to September 19, with an average daily high temperature above 78°F. The hottest month of the year in Saint Joseph is July, with an average high of 88°F and low of 68°F.

The cold season lasts for 3.0 months, from November 29 to February 26, with an average daily high temperature below 47°F. The coldest month of the year in Saint Joseph is January, with an average low of 19°F and high of 38°F.

In Saint Joseph, 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 Joseph begins around June 9 and lasts for 4.6 months, ending around October 29.

The clearest month of the year in Saint Joseph is August, during which on average the sky is clear, mostly clear, or partly cloudy 71% of the time.

The cloudier part of the year begins around October 29 and lasts for 7.3 months, ending around June 9.

The cloudiest month of the year in Saint Joseph is February, during which on average the sky is overcast or mostly cloudy 51% 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 Joseph varies significantly throughout the year.

The wetter season lasts 5.9 months, from March 29 to September 26, with a greater than 26% chance of a given day being a wet day. The month with the most wet days in Saint Joseph is June, with an average of 12.5 days with at least 0.04 inches of precipitation.

The drier season lasts 6.1 months, from September 26 to March 29. The month with the fewest wet days in Saint Joseph is January, with an average of 3.0 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 Joseph changes throughout the year.

Rain alone is the most common for 11 months, from January 22 to December 26. The month with the most days of rain alone in Saint Joseph is June, with an average of 12.5 days.

Snow alone is the most common for 3.9 weeks, from December 26 to January 22. The month with the most days of snow alone in Saint Joseph is January, with an average of 1.3 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 Joseph experiences extreme seasonal variation in monthly rainfall.

Rain falls throughout the year in Saint Joseph. The month with the most rain in Saint Joseph is June, with an average rainfall of 4.6 inches.

The month with the least rain in Saint Joseph is January, with an average rainfall of 0.4 inches.

Snowfall

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

The snowy period of the year lasts for 4.2 months, from November 15 to March 22, with a sliding 31-day snowfall of at least 1.0 inches. The month with the most snow in Saint Joseph is December, with an average snowfall of 3.4 inches.

The snowless period of the year lasts for 7.8 months, from March 22 to November 15. The least snow falls around July 24, with an average total accumulation of 0.0 inches.

The length of the day in Saint Joseph varies significantly over the course of the year. In 2025, the shortest day is December 21, with 9 hours, 21 minutes of daylight; the longest day is June 20, with 15 hours, 0 minutes of daylight.

The earliest sunrise is at 5:50 AM on June 14, and the latest sunrise is 1 hour, 58 minutes later at 7:48 AM on November 1. The earliest sunset is at 4:54 PM on December 7, and the latest sunset is 3 hours, 57 minutes later at 8:51 PM on June 27.

Daylight saving time (DST) is observed in Saint Joseph during 2025, starting in the spring on March 9, lasting 7.8 months, and ending in the fall on November 2.

The figure below presents a compact representation of key lunar data for 2025. 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 Joseph experiences extreme seasonal variation in the perceived humidity.

The muggier period of the year lasts for 3.7 months, from May 29 to September 19, during which time the comfort level is muggy, oppressive, or miserable at least 17% of the time. The month with the most muggy days in Saint Joseph is July, with 20.1 days that are muggy or worse.

The least muggy day of the year is February 8, 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 Joseph experiences significant seasonal variation over the course of the year.

The windier part of the year lasts for 7.4 months, from October 12 to May 24, with average wind speeds of more than 10.3 miles per hour. The windiest month of the year in Saint Joseph is March, with an average hourly wind speed of 12.2 miles per hour.

The calmer time of year lasts for 4.6 months, from May 24 to October 12. The calmest month of the year in Saint Joseph is August, with an average hourly wind speed of 8.3 miles per hour.

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

The wind is most often from the south for 8.4 months, from April 2 to December 13, with a peak percentage of 52% on July 5. The wind is most often from the north for 3.6 months, from December 13 to April 2, with a peak percentage of 34% on January 1.

To characterize how pleasant the weather is in Saint Joseph 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 Joseph for general outdoor tourist activities is from late May to mid September, with a peak score in the last week of August.

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 Joseph for hot-weather activities is from late June to mid 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 Joseph typically lasts for 6.0 months (182 days), from around April 15 to around October 14, rarely starting before March 28 or after May 3, and rarely ending before September 25 or after November 3.

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 Joseph should appear around March 24, only rarely appearing before March 10 or after April 14.

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 29 to August 24, with an average daily incident shortwave energy per square meter above 6.0 kWh. The brightest month of the year in Saint Joseph is July, with an average of 6.9 kWh.

The darker period of the year lasts for 3.2 months, from November 4 to February 9, with an average daily incident shortwave energy per square meter below 3.0 kWh. The darkest month of the year in Saint Joseph is December, with an average of 2.1 kWh.

For the purposes of this report, the geographical coordinates of Saint Joseph are 39.769 deg latitude, -94.847 deg longitude, and 883 ft elevation.

The topography within 2 miles of Saint Joseph contains only modest variations in elevation, with a maximum elevation change of 276 feet and an average elevation above sea level of 898 feet. Within 10 miles also contains only modest variations in elevation (400 feet). Within 50 miles contains only modest variations in elevation (636 feet).

The area within 2 miles of Saint Joseph is covered by artificial surfaces (83%) and trees (12%), within 10 miles by cropland (74%) and trees (14%), and within 50 miles by cropland (82%).