The best times to visit Sullivan for ideal weather are

April 16th to June 17th

based on average temperature and humidity from NOAA (the National Oceanic and Atmospheric Administration). Read below for more weather and travel details.



Other Sullivan Travel Info

Weather in Sullivan


Average temperatures in Sullivan vary drastically. Considering humidity, temperatures feel cold for about half of the year and otherwise nice with a fair chance of precipitation about half of the year. The area is less temperate than some — in the 32nd percentile for pleasant weather — compared to tourist destinations worldwide. Weeks with ideal weather are listed above. If you’re looking for the very warmest time to visit Sullivan, the hottest months are August, July, and then June. See average monthly temperatures below. The warmest time of year is generally early to mid August where highs are regularly around 91.3°F (32.9°C) with temperatures rarely dropping below 69.2°F (20.7°C) at night.

Sullivan Temperatures (Fahrenheit)


Sullivan Temperatures (Celsius)


“Feels-Like” Temperatures

The way we experience weather isn’t all about temperature. Higher temperatures affect us much more at higher humidity, and colder temperatures feel piercing with high winds. Our perceived temperatures factor in humidity and wind chill to better represent how hot or cold the day feels to a person.

Sullivan Perceived Temperature (F)


Sullivan Perceived Temperature (C)



Average Sullivan Temperatures by Month

Daily highs (averaged for the month) usually give the best indication of the weather. A significantly lower mean and low generally just means it gets colder at night.

Show Fahrenheit

Month Avg. High (°F) Avg. Mean (°F) Avg. Low (°F)
Jan 40.6 29.6 21
Feb 42.8 32.5 24.5
Mar 60.6 47.9 38.2
Apr 66.8 55.1 44.9
May 75.2 64.7 55.5
Jun 84.2 74 64.8
Jul 86.7 75.7 66.2
Aug 88.8 76.8 67
Sep 78.8 67.9 59.2
Oct 66.2 55.7 47.1
Nov 57.4 46.7 37.8
Dec 42.8 33.1 25.2

Show Celsius

Month Avg. High (°C) Avg. Mean (°C) Avg. Low (°C)
Jan 4.8 -1.3 -6.1
Feb 6 0.3 -4.2
Mar 15.9 8.8 3.4
Apr 19.3 12.8 7.2
May 24 18.2 13.1
Jun 29 23.3 18.2
Jul 30.4 24.3 19
Aug 31.6 24.9 19.4
Sep 26 19.9 15.1
Oct 19 13.2 8.4
Nov 14.1 8.2 3.2
Dec 6 0.6 -3.8



Precipitation (Rain or Snow)

If dry weather is what you’re after, the months with the lowest chance of significant precipitation in Sullivan are January, November, and then August. Note that we define “significant precipitation” as .1 inches or more in this section. The lowest chance of rain or snow occurs around late January and early February. For example, on the week of January 29th there are no days of precipitation on average. By contrast, it’s most likely to rain or snow in late March with an average of 3 days of significant precipitation the week of March 26th.

When can you find snow in Sullivan? Weather stations report no annual snow. Please note that a value of 0 for snow in the graph below may either mean there was no snow, or that snow is unreported.

Chance of Precipitation

The graph below shows the % chance of rainy and snowy days in Sullivan.

Days with precipitation

Snow on the Ground

The graph below shows the average snow on the ground in Sullivan (in).

Snow depth

Average Rain and Snow by Month

Show Inches

Month Daily Chance of Rain Average Snow Depth (in) Total Precipitation (in)
Jan 10% 0 2.2
Feb 16% 0 2.4
Mar 22% 0 4.2
Apr 30% 0 4.7
May 32% 0 6
Jun 29% 0 5.3
Jul 27% 0 5.9
Aug 14% 0 2.9
Sep 22% 0 6.2
Oct 18% 0 5
Nov 12% 0 1.5
Dec 20% 0 2.5

Show Centimeters

Month Daily Chance of Rain Average Snow Depth (cm) Total Precipitation (cm)
Jan 10 0 5.6
Feb 16 0 6.1
Mar 22 0 10.7
Apr 30 0 11.9
May 32 0 15.2
Jun 29 0 13.5
Jul 27 0 15
Aug 14 0 7.4
Sep 22 0 15.7
Oct 18 0 12.7
Nov 12 0 3.8
Dec 20 0 6.4


Humidity and Wind

Sullivan has some high humidity months, with other comfortably humid months. The least humid month is April (51.3% relative humidity), and the most humid month is June (67.1%).

Wind in Sullivan is usually moderate. The windiest month is December, followed by April and March. December’s average wind speed of around 9.4 knots (10.8 MPH or 17.4 KPH) is considered “a gentle breeze.” Maximum sustained winds (the highest speed for the day lasting more than a few moments) are at their highest in late March where average top sustained speeds reach 17.9 knots, which is considered a fresh breeze.

Relative Humidity (%)

The graph below shows the average % humidity by month in Sullivan.

Avg. Relative Humidity


The graph below shows wind speed (max and average) in knots.

Max Sustained Wind
Average Daily Wind

Average Wind Speeds

Show Wind Speeds

All wind speeds are in knots. 1 knot = 1.15 MPH or 1.85 KPH.

Month Avg. Wind Avg. Wind Feel Sustained High Wind High Wind Feel
Jan 8.8 Gentle breeze 14.9 Significant breeze
Feb 8.7 Gentle breeze 14.6 Significant breeze
Mar 9.2 Gentle breeze 15.6 Significant breeze
Apr 9.2 Gentle breeze 15.9 Significant breeze
May 6.9 Light breeze 13.3 Significant breeze
Jun 6.4 Light breeze 13.3 Significant breeze
Jul 5.7 Light breeze 11.7 Significant breeze
Aug 5.9 Light breeze 11.4 Significant breeze
Sep 5.6 Light breeze 10.8 Significant breeze
Oct 7.9 Gentle breeze 13.8 Significant breeze
Nov 7.9 Gentle breeze 13.1 Significant breeze
Dec 9.4 Gentle breeze 15.7 Significant breeze

Show Relative Humidity by Month

Month Avg. Relative Humidity
Jan 57.9%
Feb 56.1%
Mar 53.4%
Apr 51.3%
May 63.2%
Jun 67.1%
Jul 65.8%
Aug 61%
Sep 66.1%
Oct 62.9%
Nov 53.7%
Dec 63.6%


Is it Safe to Travel to Sullivan?

Our best data indicates this area is generally safe. As of Oct 07, 2019 there are no travel advisories or warnings for the United States; exercise normal security precautions. Check this page for any recent changes or regions to avoid: Travel Advice and Advisories. This advisory was last updated on Sep 23, 2019.


The Busiest and Least Crowded Months

The busiest month for tourism in Sullivan, MO, US is March, followed by May and February. Prices for hotels and flights will be most expensive during these months, though you can save if you purchase well in advance. Tourists are unlikely to visit Sullivan in November. Those willing to visit at these times will likely find it the least expensive month.

Estimated Tourism by Month


Most Popular Months to Visit

Tourists Seeking Accommodations

Tourism graph is based on Google searches for services used by tourists relative to the rest of the year. Tourism data for this area is extrapolated based on nearby areas. Displayed data is calculated relative to the peak, so a score of 44 in November means 44% of the tourists vs. March.



Overall Sullivan Travel Experience by Season

Spring (March through May)

Humidity and temperatures combine to make this season feel moderate. Highs range from 81°F (27.2°C) and 49.1°F (9.5°C) with warmer temperatures in the later months. Rain is somewhat common with 7 to 10 days of significant precipitation per month. Spring is the busiest for tourism, which makes it a good time for those looking for things to do.

Summer (June through August)

The middle-year months have very comfortable weather with high temperatures that are quite warm. These months see moderate precipitation with 4 to 9 days of precipitation per month. June – August is the second busiest season for tourism in Sullivan, so lodging and other accommodations may cost slightly more.

Fall (September through November)

Fall daily highs range from 79.9°F (26.6°C) and 52°F (11.1°C), which will feel comfortable given the humidity and wind. It rains or snows a significant amount: 4 to 7 days per month. Tourism is the slowest during these months due to the weather, so hotels may be affordably priced.

Winter (December through February)

Weather is far too cold this time of year in Sullivan to be enjoyable for warm weather travelers. The average high during this season is between 49.1°F (9.5°C) and 38.5°F (3.6°C). On average, it rains or snows a fair amount: 3 to 6 times per month. These times of year are fairly slow with tourists.


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