Walking in the rain is not comfortable at all. Unfortunately, Japan is a rainy country. In Tokyo, the annual rainfall for the past thirty years was 1,407 millimeters, much more than those of the major cities in the world; 750 mm in London, 650 mm in Paris and 1,070 mm in New York city. This is the reason why Tokyo Disneyland, which is a copy of Disneyland in Anaheim, California, has a roof in its Main Street. The following are climatological data (average based on the thirty-year records) in Yokohama, the neighboring city of Kamakura: (Temperature in Celsius.)
The earliest sunrise is observed between June 5 and June 21 at 4:26 a.m. for about two weeks, while the latest sunset is at around 19:00 p.m. in late June through early July. Likewise, the sun rises latest in early January and sets earliest in early December.
Japan Meteorological Agency forecast weather every day by region, which is updated three times a day,
but it is often unreliable, spring and fall in particular, when weather
is changeable. Weatherpersons continue to look ahead and rarely look back.
If the forecast was off the mark and weatherpersons refer to wrong prediction,
they usually say high atmospheric pressure moved faster or late than had
been expected. Forecast is most in need when the weather is changeable.
However, the accuracy rates in these seasons are, I think, less than 50
percent. Meteorologists makes fantastic weekly forecast every day covering
seven days to come. First of all, they cannot predict precisely even several
hours ahead. How come they can forecast seven days' weather? Friend of
mine living in Vancouver, Canada once told me forecast up there is not
reliable either, saying that the meteorologists often say the weather is
fine even when it is raining outside. The most important device they need,
he said, is a window. The same holds true in Japan. Those meteorologists
are too busy dealing with many sophisticated computers and other equipment
to look out the window.
A typical forecast in a spring morning in English dailies reads like this: "It will rain periodically throughout the morning. In the afternoon, scattered rain is possible." In case of Tokyo, for example, the meteorologists quite often forecast like this, "Today's weather in Tokyo will be fine and partly cloudy with occasional rains depending on regions. Precipitation probability is 20 percent". Hearing this, those who commute to Tokyo may bring an umbrella lest it should shower in central Tokyo, but most often, it never showers. Tokyo stretches toward northwest for 60 to 70 kilometers, where mountains are as high as 1,500 meters and few people are living. It may have showered in those remote mountains as predicted. As a result, the forecast is credited as correct. Sometimes, they even say "The rain started earlier (or later) than had been expected", and hardly admit the forecast was wrong. If an economist is an expert who will know tomorrow why the things he predicted yesterday did not happen today, a weatherman is an expert who will never look back no matter how wrong his forecast turned out. Meteorologists often boast that the accuracy rate of their forecast is more than 80 percent. A well-known meteorologist said in a radio talk show that he did not understand why people think the accuracy rate of the forecast is less than 60 percent. It is simply because meteorologists are unable to forecast correctly when the weather is changeable. In mid-winter and mid-summer, we do not need forecast since the weather is quite stable. Forecast in need is forecast indeed. Worse still, they hardly make an apology no matter how wrong their forecast proved to be. The word 'apology' is missing in their vocabulary.
There was an old gentlemen in Tokyo who had checked every day on whether or not Mt. Fuji, nearly 100 kilometers away, was visible from the spot near his home. He had made the survey exactly at 8:00 a.m. every day for 16 years from 1973 through 1988. The average number of days he saw Mt. Fuji by month were; 17.9 days in January, 12.7 in December, 11.7 in February, 7.1 in November and 6.3 in March. Considering February has 28 or 29 days, it is as good as December in terms of percentage. If Mt. Fuji can be seen from Tokyo, then we can almost certainly see it from Kamakura as well. During April through October, on the other hand, Mt. Fuji rarely shows up. This is far better indication than the computer-driven forecast.
Incidentally, we Japanese do not have daylight-saving time, which are honored by most of the developed countries. Once introduced briefly during the postwar Occupation period, it was soon repealed, and have never been re-instated in the belief that it does not contribute to energy saving but result only in longer working hours.
From late November to mid-February:
Weather is best for visiting and walking around Kamakura. Though it is chilly and daytime is short from December to February, weather is fine with almost no rain. During the first three days of New Year, however, Tsurugaoka Hachimangu Shrine is awfully crowded with shoulder-to-shoulder visitors.
March, April and May:
It is comfortable to go out, but weather is changeable and it rains very often. Weather forecast is least reliable. Bringing an umbrella is suggested even when it is sunny in the morning, particularly in March. The weather will be more stable in April and May. Be aware that one week from April 29 thorough May 5 is called the Golden Week in Japan with four National Holidays concentrating on this week. With comfortable climate, sightseers are everywhere across the country.
It will get warmer day by day. In mid-June, the rainy season starts and blue skies can rarely be seen. Not heavy rain, but days of overcast skies or light drizzle are more common, making everything including our spirit wet. (Umbrella is one of the best buy in Japan.) According to the Meteorological Agency, the rainy season ends on July 20 on average, and precipitation during the season is 268 millimeters in Greater Tokyo. It is unlucky for Japanese the summer solstice is right in the middle of rainy season, when north European and Canadian people can enjoy the best season with clear sky, low humidity and no rain.
Rainy or cloudy days continue during the first half of the month. As the rainy season draws to a close in mid-July, torrential rainfalls are likely depending on regions, western part of Japan in particular. Downpour sometimes amounts to 500 millimeters in a couple of days, approximately one-third the annual precipitation, causing flood and landslide. Once this heavy rain attacks the Tokyo area, transportation systems including the Yokosuka Line would be paralyzed. Be careful. The rainy season usually ends up dramatically around July 20 often with thunderstorm and rain. Once the rainy season is over, we have sunny days, though too warm and humid. As is shown in the table above, relative humidity in July reaches over 80 percent, and the temperature up 35 degrees in Celsius to boot. Discomfort Index exceeds 85, the level everybody feels uncomfortable.
A long spell of heat weather. Hot and sticky days continue. Backyards of temples are usually overgrown with bushes and grasses. Bees and mosquitos may attack visitors.
In early part of September, the heat of late summer still lingers, while it gets cooler in the morning and evening with shorter daytime. Typhoon season starts at this time. One typhoon after another attack the Japanese archipelago bringing torrential rains and gusty winds. Meteorologists are busy predicting its course and timing. Should a typhoon hit the Tokyo area, transportation system would be crippled. A mild climate will come with the equinox day. Again the weather becomes changeable.
A good season to visit anywhere in Japan.
Weather is stable with the temperature gradually going down.
One of the unfavorable facts about the Japanese climate is that the summer solstice falls right on the middle of the rainy season as noted above, and after the rainy season, high humidity atmosphere brought from the Pacific Ocean make us very uncomfortable, and therefore, summer is not the best season to visit Kamakura. Winter seems to be the best, with clear sky almost every day and with less visitors. Temperature never goes down below the freezing point, and it rarely snows. Records show that it used to snow a dozen or so time every winter before World War II, but no longer due in part to the global warming? Be careful, however, that relative humidity may sometime go below 20 percent. Spring and autumn are also good, though popular spots are always crowded.
Japan is an earthquake-prone country. The March 11, 2011 earthquake with a magnitude of 9.0 off the Pacific coast of Tohoku (Aomori, Iwate, Miyagi and Ibaraki prefectures) followed by massive tsunami, which reached heights of up to 40.5 meters (133 ft) in Miyako, killed nearly 20,000 people and washed away tens of thousands houses.
In the Tokyo and Yokohama area, the Great Kanto Earthquake hit on September 1, 1923, killing nearly 180,000 people, and many cultural assets in Kamakura were lost or damaged. The central government's Earthquake Research Promotion Center states there is a 70 percent probability a quake of the same scale will hit the southern Kanto region within 30 years.
The devastating tsunami of March 11 made every local government in the Kanto area to reexamine how serious the damage would be should the second Great Kanto Earthquake strike. A seismologist at Waseda University says tsunami at Kamakura would be as high as 14.4 meters, most likely to hit Tsurugaoka Hachinagu Shrine and Kotoku-in (The Great Buddha).
Hiratsuka city of Kanagawa located west of Kamakura released on YouTube a computer-generated simulation of a 10-meter-high tsunami hitting the city. You can view it here.