The best times to visit Karatsu for ideal weather are

April 2nd to June 24th


September 24th to November 18th

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



Other Karatsu Travel Info

Weather in Karatsu


Average temperatures in Karatsu vary drastically. Considering humidity, temperatures feel nice some of the year, but often too hot in the summer and cold in the winter with a chance of rain or snow throughout most of the year. The area is less temperate than some — in the 27th 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 Karatsu, the hottest months are August, July, and then September. See average monthly temperatures below. The warmest time of year is generally early to mid August where highs are regularly around 93.5°F (34.2°C) with temperatures rarely dropping below 77.5°F (25.3°C) at night.

Karatsu Temperatures (Fahrenheit)


Karatsu 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.

Karatsu Perceived Temperature (F)


Karatsu Perceived Temperature (C)



Average Karatsu 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 49.7 42 33.9
Feb 53.6 45.4 36.6
Mar 59.6 50.9 41.1
Apr 68.8 59 48.6
May 78.3 68.3 58.1
Jun 81.6 74.2 67.7
Jul 88.8 81.4 75
Aug 91.4 82.8 76.1
Sep 85.5 76.7 69.3
Oct 76.2 66.8 57.9
Nov 64.4 55.8 47.3
Dec 53.1 45.6 37.7

Show Celsius

Month Avg. High (°C) Avg. Mean (°C) Avg. Low (°C)
Jan 9.8 5.6 1.1
Feb 12 7.4 2.6
Mar 15.3 10.5 5.1
Apr 20.4 15 9.2
May 25.7 20.2 14.5
Jun 27.6 23.4 19.8
Jul 31.6 27.4 23.9
Aug 33 28.2 24.5
Sep 29.7 24.8 20.7
Oct 24.6 19.3 14.4
Nov 18 13.2 8.5
Dec 11.7 7.6 3.2



Precipitation (Rain or Snow)

If dry weather is what you’re after, the months with the lowest chance of significant precipitation in Karatsu are January, October, and then December. Note that we define “significant precipitation” as .1 inches or more in this section. The lowest chance of rain or snow occurs around early to mid January. For example, on the week of January 8th there are no days of precipitation on average. By contrast, it’s most likely to rain or snow in early July with an average of 4 days of significant precipitation the week of July 2nd.

When can you find snow in Karatsu? Weather stations report a very small amount of seasonal snow likely to be deepest around January, especially close to early January. The best time to ski (if at all) in Karatsu is often around around January 1st when fresh powder is deepest. 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 Karatsu.

Days with precipitation

Snow on the Ground

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

Snow depth

Average Rain and Snow by Month

Show Inches

Month Daily Chance of Rain Average Snow Depth (in) Total Precipitation (in)
Jan 12% 0.4 1.7
Feb 22% 0 3.2
Mar 25% 0 4.8
Apr 23% 0 5.5
May 22% 0 5.6
Jun 38% 0 12.6
Jul 36% 0 15
Aug 32% 0 11.7
Sep 20% 0 4.1
Oct 16% 0 4.6
Nov 19% 0 3.7
Dec 16% 0 3

Show Centimeters

Month Daily Chance of Rain Average Snow Depth (cm) Total Precipitation (cm)
Jan 12 1 4.3
Feb 22 0 8.1
Mar 25 0 12.2
Apr 23 0 14
May 22 0 14.2
Jun 38 0 32
Jul 36 0 38.1
Aug 32 0 29.7
Sep 20 0 10.4
Oct 16 0 11.7
Nov 19 0 9.4
Dec 16 0 7.6


Humidity and Wind

Karatsu has some high humidity months, with other comfortably humid months. The least humid month is April (51.5% relative humidity), and the most humid month is July (68.2%).

Wind in Karatsu is usually calm. The windiest month is July, followed by March and April. July’s average wind speed of around 6.7 knots (7.7 MPH or 12.4 KPH) is considered “a light breeze.” Maximum sustained winds (the highest speed for the day lasting more than a few moments) are at their highest in early to mid July where average top sustained speeds reach 14.4 knots, which is considered a moderate breeze.

Relative Humidity (%)

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

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 5.5 Light breeze 11.8 Significant breeze
Feb 6.2 Light breeze 12.8 Significant breeze
Mar 6.5 Light breeze 13.5 Significant breeze
Apr 6.4 Light breeze 13.5 Significant breeze
May 6 Light breeze 12.5 Significant breeze
Jun 6.3 Light breeze 12.8 Significant breeze
Jul 6.7 Light breeze 13.1 Significant breeze
Aug 6.3 Light breeze 12.9 Significant breeze
Sep 5.9 Light breeze 12.1 Significant breeze
Oct 6.3 Light breeze 12.5 Significant breeze
Nov 5.6 Light breeze 11.9 Significant breeze
Dec 5.7 Light breeze 12.1 Significant breeze

Show Relative Humidity by Month

Month Avg. Relative Humidity
Jan 57.1%
Feb 56%
Mar 53.2%
Apr 51.5%
May 52.8%
Jun 67.8%
Jul 68.2%
Aug 66.1%
Sep 62.8%
Oct 57.7%
Nov 60.2%
Dec 59.9%


Is it Safe to Travel to Karatsu?

Our best data indicates this area is generally safe, except in a few regions. As of Oct 07, 2019 there are regional travel advisories for Japan; exercise normal security precautions and avoid some areas. Check this page for any recent changes or regions to avoid: Travel Advice and Advisories. This advisory was last updated on Oct 01, 2019.


The Busiest and Least Crowded Months

The busiest month for tourism in Karatsu, Japan is February, followed by March and July. 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 Karatsu in October. 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 48 in October means 48% of the tourists vs. February.



Overall Karatsu Travel Experience by Season

Spring (March through May)

Humidity and temperatures combine to make this season feel moderate. Highs range from 80.4°F (26.9°C) and 55.2°F (12.9°C) with warmer temperatures in the later months. Rain is somewhat common with 7 to 8 days of significant precipitation per month. Spring is fairly slow for tourism, which makes it a good time for those looking for deals.

Summer (June through August)

The middle-year months have very comfortable weather with high temperatures that are quite warm. These months see the most precipitation with 10 to 11 days of precipitation per month. June – August is the busiest season for tourism in Karatsu, so lodging and other accommodations may cost more than usual.

Fall (September through November)

Fall daily highs range from 87.4°F (30.8°C) and 59.5°F (15.3°C), which will feel very nice given the humidity and wind. It rains or snows a significant amount: 5 to 6 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 too cold this time of year in Karatsu to be enjoyable for warm weather travelers. The average high during this season is between 57.5°F (14.2°C) and 48.9°F (9.4°C). On average, it rains or snows a fair amount: 4 to 6 times per month. These times of year are the second busiest with tourists.


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