Lake Kawaguchi is colder than Tokyo in all twelve months of the Japan Meteorological Agency’s 1991 to 2020 normals, and the gap is widest in January: the lake station averages minus 0.4C against Tokyo’s 5.4C. It also records 97 cm of snowfall in a normal year against Tokyo’s 8 cm, while taking 87.5 hours more sunshine than the capital.
The figures below come from the agency’s normals table for the Kawaguchiko station in Yamanashi Prefecture and the Tokyo station, and from Fujikawaguchiko Town’s own population page. Where a number is a difference or a ratio, the arithmetic is mine and is marked as such.
The lake is colder than Tokyo every month, by 3.8C in July and 5.8C in January
Both stations publish mean monthly air temperature on the same footing: the statistics period is 1991 to 2020 and the record length is 30 years. That makes a month-by-month subtraction safe to do, which is not true of every column on these two tables.
The Kawaguchiko station’s annual mean is 11.0C and Tokyo’s is 15.8C, a difference of 4.8C. The monthly gap never closes. July is the narrowest month at 3.8C and January the widest at 5.8C. One month of the year, January, has a mean below freezing at the lake; Tokyo has none. The subtractions in the right-hand column are mine.
| Month | Kawaguchiko mean (C) | Tokyo mean (C) | Difference (my subtraction) |
|---|---|---|---|
| January | -0.4 | 5.4 | 5.8 |
| February | 0.6 | 6.1 | 5.5 |
| March | 4.2 | 9.4 | 5.2 |
| April | 9.5 | 14.3 | 4.8 |
| May | 14.3 | 18.8 | 4.5 |
| June | 17.8 | 21.9 | 4.1 |
| July | 21.9 | 25.7 | 3.8 |
| August | 22.5 | 26.9 | 4.4 |
| September | 18.7 | 23.3 | 4.6 |
| October | 13.0 | 18.0 | 5.0 |
| November | 7.5 | 12.5 | 5.0 |
| December | 2.3 | 7.7 | 5.4 |
| Year | 11.0 | 15.8 | 4.8 |
The daily extremes move the same way. January’s normal daily minimum at the lake is minus 5.7C against Tokyo’s 1.2C, and the normal daily maximum in January is 5.5C against 9.8C. In August the lake’s normal daily maximum is 28.1C, which is 3.2C below Tokyo’s 31.3C by my subtraction.
Four months have a normal daily minimum below freezing
The mean temperature understates how the nights behave. Counting the twelve monthly figures for normal daily minimum temperature at the Kawaguchiko station, four of them sit below zero: January at minus 5.7C, February at minus 4.8C, March at minus 1.3C and December at minus 2.9C. The remaining eight run 3.7C in April, 8.9C in May, 13.7C in June, 18.0C in July, 18.5C in August, 14.8C in September, 8.7C in October and 2.2C in November.
The normal daily maximum never falls below freezing in any month. The coldest is January at 5.5C, and the warmest is August at 28.1C. The spread between the coldest monthly minimum and the warmest monthly maximum is therefore 33.8C across the year, which is my subtraction and not a figure the agency prints.
That split matters for packing rather than for sightseeing. A March visit sits in a month whose normal daily mean is 4.2C and whose normal daily minimum is below zero, while the same month’s normal daily maximum is 10.5C.
September is the wettest month at the lake, not June
The rainy season is not where the water falls heaviest here. The Kawaguchiko station’s wettest normal month is September at 264.7 mm, followed by October at 230.0 mm. June delivers 157.1 mm and July 178.4 mm, both below the September and October figures. December is the driest at 49.8 mm and February second driest at 55.4 mm, with January third at 60.9 mm.
Tokyo’s own table peaks in a different month. The capital’s wettest normal is October at 234.8 mm, with September second at 224.9 mm. So the two places do not even agree on which autumn month to avoid, and the lake’s September figure is the higher of the two by 39.8 mm, again my subtraction.
The annual totals, by contrast, are almost identical: 1,585.9 mm at the lake and 1,598.2 mm in Tokyo, a difference of 12.3 mm. A year at Lake Kawaguchi is not a wetter year than a year in Tokyo. It is a year with the water redistributed into the autumn.
A normal year brings 97 cm of snowfall and a deepest snow depth of 36 cm
Snow is where the two stations separate sharply. The agency gives the Kawaguchiko station an annual snowfall depth total of 97 cm, a largest daily snowfall total of 29 cm, and a deepest snow depth of 36 cm. Tokyo’s three figures on the same 1991 to 2020 footing are 8 cm, 5 cm and 6 cm. The lake’s snowfall total is about 12 times Tokyo’s, by my division.
By month, the snowfall arrives in January (37 cm), February (28 cm), March (20 cm), December (7 cm), April (4 cm) and November (1 cm). The deepest snow depth normals for those months are 25 cm, 24 cm, 16 cm, 6 cm, 4 cm and 1 cm. From May to October all three snow columns carry a dash, which the agency’s key to the value columns defines as the phenomenon not occurring.
One caution on the day counts. The nineteen columns of the Kawaguchiko table do not share a footing, and the agency prints the statistics period and the record length for each column separately. Thirteen columns, among them temperature, precipitation, sunshine and the three snow columns, run from 1991 to 2020 over 30 years. The snow-day and fog-day columns run from 2003 to 2020 over 18 years. The cloud-amount and thunder-day columns run from 1991 to 2003 over 13 years, and every value in them carries the agency’s @ mark, which the legend defines as a reference value that cannot be used for differences from the normal or ratios to the normal. Two columns print three slashes throughout, with a record length of 0 years. The 36.7 snow days a year and Tokyo’s 8.5 are therefore not measured over the same span, while the snowfall and snow-depth totals sit on matching 30-year columns at both stations.
Fog is counted on 43.8 days a year, and the station has no sea-level pressure normal at all
The Kawaguchiko station records fog on 43.8 days in a normal year, against 1.3 days at Tokyo, a factor of about 34 by my division. November is the highest single month at 7.2 days, with October at 6.3 days and June at 3.9 days. As with the snow days, the lake’s fog column rests on the 2003 to 2020 period and Tokyo’s on 1991 to 2020.
The same table carries a quieter sign of where the station sits. Tokyo’s row prints both a local mean pressure of 1,010.9 hPa and a sea-level mean of 1,013.8 hPa. The Kawaguchiko row prints a local mean of 915.2 hPa and three slashes where the sea-level figure would be, with a record length of 0 years. The global solar radiation column prints three slashes in the same way. The agency does not publish those two normals for this station at all, so there is no sea-level pressure figure for Lake Kawaguchi to quote.
The lake takes 87.5 more hours of sunshine a year than Tokyo
Against the cold and the fog sits a figure that runs the other way. Annual sunshine duration at the Kawaguchiko station is 2,014.2 hours and at Tokyo 1,926.7 hours, a difference of 87.5 hours in the lake’s favour by my subtraction. Both columns run 1991 to 2020 over 30 years, so the comparison is sound.
The monthly pattern explains it. The lake’s sunniest normal month is January at 212.3 hours, and December is second at 199.9 hours. Tokyo’s January is 192.6 hours. The lake’s thin months are June at 122.8 hours and September at 122.5 hours, and September is also the lake’s wettest month at 264.7 mm. Mean relative humidity is 73 per cent at the lake against 65 per cent in Tokyo, and mean wind speed 1.9 m/s against 2.9 m/s.
The clear, cold weather is therefore a winter feature of this station rather than a summer one: January carries both the highest sunshine total, at 212.3 hours, and, tied with May, the lowest monthly fog count, at 2.1 days. The autumn months that bring the rain also bring the fog, with October at 230.0 mm of precipitation and 6.3 fog days and November at 7.2 fog days. The viewpoints on the north shore, including Oishi Park and the Sakura Walk, are covered separately in our piece on the north shore of Lake Kawaguchiko.
Fujikawaguchiko Town counted 27,049 residents on 1 October 2026
The lake sits inside Fujikawaguchiko Town, and the town publishes its resident-register count monthly. On 1 October 2026 the register held 27,049 people, down 12 on the previous month, in 12,391 households, down 3. The split was 13,313 men, down 15, and 13,736 women, up 3. The two sexes add to the printed total and the two monthly changes add to the printed change of minus 12; both additions are mine.
That is the count for the whole municipality, not for the lakeshore alone. The town office is at 1700 Funatsu, the register page is maintained by the residents’ affairs division, and the site lists three branch offices beside the main hall, at Katsuyama, Ashiwada and Kamikuishiki.
Alongside the monthly figure the town publishes a second set of counts broken down by district. The 27,049 total is the municipality-wide figure from the monthly set rather than from the district one.
Sources Checked
Japan Meteorological Agency – climate normals table for the Kawaguchiko station, Yamanashi Prefecture
Confirmed the annual mean temperature of 11.0C; the twelve monthly means of -0.4, 0.6, 4.2, 9.5, 14.3, 17.8, 21.9, 22.5, 18.7, 13.0, 7.5 and 2.3C; January’s normal daily maximum of 5.5C and minimum of -5.7C; August’s normal daily maximum of 28.1C; annual precipitation of 1,585.9 mm with September at 264.7 mm, October at 230.0 mm, July at 178.4 mm, June at 157.1 mm, January at 60.9 mm, February at 55.4 mm and December at 49.8 mm; annual snowfall depth total of 97 cm, largest daily snowfall total of 29 cm and deepest snow depth of 36 cm, with monthly snowfall of 37, 28, 20, 4, 1 and 7 cm in January, February, March, April, November and December and monthly deepest depths of 25, 24, 16, 4, 1 and 6 cm; 36.7 snow days and 43.8 fog days a year on the 2003 to 2020 period of 18 years, with November at 7.2 fog days, October at 6.3, June at 3.9 and January and May tied lowest at 2.1; annual sunshine of 2,014.2 hours with January at 212.3 and December at 199.9; mean relative humidity of 73 per cent; mean wind speed of 1.9 m/s; local mean pressure of 915.2 hPa with no sea-level pressure normal and no global solar radiation normal published, both shown with a record length of 0 years; and the statistics period and record length of all nineteen columns, thirteen of them on 1991 to 2020 over 30 years, two on 2003 to 2020 over 18 years, two on 1991 to 2003 over 13 years and two printing three slashes with a record length of 0 years.
https://www.data.jma.go.jp/stats/etrn/view/nml_sfc_ym.php?prec_no=49&block_no=47640
Japan Meteorological Agency – climate normals table for the Tokyo station
Confirmed the annual mean temperature of 15.8C; the twelve monthly means of 5.4, 6.1, 9.4, 14.3, 18.8, 21.9, 25.7, 26.9, 23.3, 18.0, 12.5 and 7.7C; January’s normal daily maximum of 9.8C and minimum of 1.2C; August’s normal daily maximum of 31.3C; annual precipitation of 1,598.2 mm with October at 234.8 mm and September at 224.9 mm; annual snowfall depth total of 8 cm, largest daily snowfall total of 5 cm and deepest snow depth of 6 cm; 8.5 snow days and 1.3 fog days a year; annual sunshine of 1,926.7 hours with January at 192.6; mean relative humidity of 65 per cent; mean wind speed of 2.9 m/s; local mean pressure of 1,010.9 hPa and sea-level mean pressure of 1,013.8 hPa; all nineteen columns on the statistics period 1991 to 2020 with a record length of 30 years.
https://www.data.jma.go.jp/stats/etrn/view/nml_sfc_ym.php?prec_no=44&block_no=47662
Fujikawaguchiko Town – population and households page
Confirmed the resident-register figures for 1 October 2026 of 27,049 people (down 12 on the previous month), 13,313 men (down 15), 13,736 women (up 3) and 12,391 households (down 3); the town office address of 1700 Funatsu; and the three branch offices listed on the site, at Katsuyama, Ashiwada and Kamikuishiki.
https://www.town.fujikawaguchiko.lg.jp/jinkou/
Last updated: October 2026
