Saitama’s highest recorded temperature does not belong to Kumagaya. On the Japan Meteorological Agency’s all-time national ranking, the Saitama station of Hatoyama stands at 41.4 degrees Celsius, set on 5 August 2025, while Kumagaya — the name that travels with the reputation — stands at 41.1 degrees, set on 23 July 2018. The same table carries both, at ranks 2 and 6. If you are checking what a Saitama summer does, the normals and the records are published by station, and the two Saitama stations do not say the same thing.
Two Saitama stations sit inside the national top thirteen rows
The agency builds the ranking from each station’s own all-time highest value, so one station contributes one row, except, as the page adds, where an AMeDAS station’s statistics have been cut, in which case the first-place value of each period can appear, and it ranks two kinds of site in one list: an asterisk after a station name marks an observatory-class site and the unmarked names are AMeDAS. Kumagaya carries that asterisk and Hatoyama does not, and the two station pages start their series in December 1977 for Hatoyama and December 1896 for Kumagaya. Counting down from the top until the figures fall below 41.0 degrees gives thirteen rows, and two of them name Saitama stations. Gunma supplies three rows and Shizuoka three; Gifu supplies two; Hyogo, Tochigi and Kochi supply one each. Those tallies are our own count of the printed rows.
| Rank | Prefecture | Station | Reading | Date of the record |
|---|---|---|---|---|
| 1 | Gunma | Isesaki | 41.8 | 5 August 2025 |
| 2 | Shizuoka | Shizuoka | 41.4 | 6 August 2025 |
| 2 | Saitama | Hatoyama | 41.4 | 5 August 2025 |
| 4 | Gunma | Kiryu | 41.2 | 5 August 2025 |
| 4 | Hyogo | Kaibara | 41.2 | 30 July 2025 |
| 6 | Shizuoka | Sakuma | 41.1 | 23 July 2026 |
| 6 | Shizuoka | Hamamatsu | 41.1 | 17 August 2020 |
| 6 | Saitama | Kumagaya | 41.1 | 23 July 2018 |
| 9 | Gunma | Maebashi | 41.0 | 5 August 2025 |
| 9 | Tochigi | Sano | 41.0 | 29 July 2024 |
| 9 | Gifu | Mino | 41.0 | 8 August 2018 |
| 9 | Gifu | Kanayama | 41.0 | 6 August 2018 |
| 9 | Kochi | Egawasaki | 41.0 | 12 August 2013 |
Four of the thirteen records were set on a single day, 5 August 2025, and one was set on 23 July 2026, the latest date of the thirteen by our reading. Kumagaya’s 2018 record shares its exact calendar date, 23 July, with that 2026 reading at Sakuma. The ranking is a table of station records and nothing more; it does not say which prefecture is hot in an average summer. For that you need the normals.
Kumagaya’s normals put August daily highs at 32.3 degrees and January nights below zero
The agency’s climate normals for Kumagaya are calculated over 1991 to 2020 and give three temperature columns: monthly mean, mean daily maximum and mean daily minimum. August is the warmest month on all three, at 27.1, 32.3 and 23.3 degrees. January is the coldest on all three, at 4.3, 9.8 and minus 0.4 degrees, so the normal January night at Kumagaya is below freezing while the normal January day is close to ten degrees. Across the year the three columns read 15.4, 20.7 and 11.0 degrees.
Annual precipitation is 1,305.8 millimetres, and the wettest month is September at 198.2 millimetres, not a midsummer month; the driest is December at 30.9. Annual sunshine is 2,106.6 hours, and the sunniest month is January at 217.0 hours while the least sunny is September at 131.6 — the same month that carries the year’s highest precipitation figure. Mean relative humidity runs 65 per cent over the year, from 52 per cent in February to 76 per cent in July. Mean wind speed is 2.5 metres per second and the column headed most frequent direction gives north-west for January, February, March, April and December and east for June, July, August and September. Thunder is the column that matches the heat: Kumagaya’s normal is 20.2 thunder days a year, with 6.0 in August and 5.1 in July.
Snow is in the normals, and the deepest month averages five centimetres
Kumagaya does get snow in an average year, and the quantities are small. The normals give 16 centimetres of total snowfall depth across the year, of which January and February contribute 7 centimetres each and March and December 1 centimetre each; those four months add to the printed annual 16 by our own addition. April and November show 0, and the months from May to October print a dash in place of a figure. The largest daily total in the normals is 8 centimetres for the year. Normal maximum snow depth is 9 centimetres for the year, with February the deepest month at 5 centimetres and January at 4. Snow days average 17.7 a year, spread over six months: 6.0 in January, 5.5 in February, 3.4 in March, 2.6 in December, 0.2 in April and 0.1 in November.
Three of the nineteen normals columns are measured over 29 years, and one over none
The table prints a statistical period and a number of years above every column, and they are not all the same. Fifteen columns are 1991 to 2020 over 30 years. Mean cloud amount, fog days and thunder days are 1991 to 2019 over 29 years, and each of those three carries the at-sign that the agency’s symbol legend defines as a reference value, usable for the shape of the climate but not for working out a departure from normal. Snow days is a 30-year column and carries no symbol. The global solar radiation column has no statistical period and 0 years, and prints three slashes in every month. So the 5.3 fog days and 20.2 thunder days quoted above rest on one fewer year than the temperature and precipitation figures beside them and are printed as reference values, while the radiation column cannot be quoted at all. That count of columns is ours, taken from the header rows.
The city was assembled in three steps, and the prefecture’s heat is measured elsewhere
Saitama City is the prefectural capital and sits in the south-east of the prefecture. Its own pages date the city to May 2001, when the three cities of Urawa, Omiya and Yono merged, and record 1 April 2003 as the day it became the thirteenth designated city in Japan. At that designation nine wards were created: Nishi, Kita, Omiya and Minuma in the former Omiya City area, Chuo in the former Yono City area, and Sakura, Urawa, Minami and Midori in the former Urawa City area. The city adds a footnote that Ohara 6-chome and 7-chome, in the former Urawa City area, went into Omiya Ward rather than an Urawa-side ward. On 1 April 2005 the city absorbed Iwatsuki City and created Iwatsuki Ward, bringing the count to ten wards, which is where it stands.
The city describes itself as a junction on the east side of Japan, where six Shinkansen lines including the Tohoku and Joetsu lines meet JR and private railway lines, and it traces its older growth to a post town on the Nakasendo highway. Citizens’ Day is 1 May, chosen because the city government began on that date in 2001. The city office is at Tokiwa 6-4-4 in Urawa Ward and the page gives its office hours as 8:30 to 17:15, with Saturdays, Sundays, public holidays and the year-end and new-year period excluded and some offices keeping different hours. Neither Hatoyama nor Kumagaya is inside the city: both are separate municipalities in the same prefecture, which is why a figure labelled Saitama can mean the city, the prefecture or a weather station, and the three are not interchangeable. The prefecture next door raises the same labelling problem in its own way: Chiba is almost flat, and larger than Tokyo and Kanagawa combined.
The city names three plant emblems, and one of them carries a national designation. The city tree is the zelkova, and the city points to the avenue on the approach to Hikawa Shrine in Omiya and the zelkova avenue along Route 463 as examples. The city flower is the Siebold primrose, and its wild habitat at Tajimagahara in Sakura Ward is designated a special natural monument by the national government; the city says it removes invasive plants and burns off grass there to keep the habitat. The city flowering tree is the cherry.
The Railway Museum charges exactly 100 yen more on the day in all three individual tiers
The museum in Omiya publishes its hours as 10:00 to 17:00 with last admission at 16:30, and closes every Tuesday plus the year-end and new-year period. Tickets are sold in advance up to the day before, or on the day, and those two rows differ by the same amount in each of the three age tiers.
| Ticket | General | Primary, junior high and high school | Child aged 3 and over, not yet in school |
|---|---|---|---|
| Advance, up to the day before | 1,500 yen | 500 yen | 200 yen |
| Same day | 1,600 yen | 600 yen | 300 yen |
| Disability rate, holder plus one carer | 800 yen | 300 yen | 150 yen |
| Annual pass | 6,200 yen | 2,500 yen | 1,000 yen |
| Weekday afternoon pass, from 12:00 | 4,800 yen | 2,000 yen | 800 yen |
Subtracting the advance row from the same-day row gives 100 yen in all three tiers — our own arithmetic on the printed figures, and those are the individual rates. A group page linked from the same guide sets a separate scale once 20 or more paying visitors come together: 1,200 yen general, 400 yen for school students and 160 yen for a child aged 3 and over, against individual figures of 1,600, 600 and 300. School parties using the museum as part of school education get the group scale below 20 paying visitors as well, admission is free for tour-company couriers and teaching staff on school visits, and the museum states that the disability rate and the group rate are not applied together. The opening bullet of that page extends the free list to tour guides and coach drivers; the note under its price table does not. The price columns begin at age 3, and neither page prints a rate for a child under 3. The disability rate applies to the holder of one of the listed certificates and up to one carer, and the museum states that showing the home screen of the Mirairo ID smartphone app also qualifies; holders are asked to come straight to the entrance counter rather than buy in advance. The annual pass is valid only for the person who signs it, and the page notes that a limited Shinkalion-illustration premium version of the same pass is priced differently. The weekday afternoon pass is usable only from 12:00 on weekdays and runs one year from purchase, with a stated adjustment: if the final day of validity falls on a weekend, a public holiday or a closing day, the expiry moves back to the preceding weekday and still starts at 12:00.
Four purchase routes carry their own bullet on the page. Tickets can be bought online from the museum’s own site with no membership registration; at Seven-Eleven, Lawson and Ministop stores; and from the museum’s own ticket machine, which sells same-day tickets from 10:00 on every open day and takes transport IC cards and cash. The fourth bullet is the experience-booking ticket for the mini driving train and the E5, D51 and conductor simulators, sold through Seven Ticket only. There is accessible parking in the P3 car park at 1,000 yen per car per day, in a stated limited number of spaces, which cannot be reserved and is not discounted on presentation of a certificate, and a sentence saying that wheelchair lending is currently suspended sits in the page’s HTML inside a comment, so the page does not display it.
Sources Checked
Japan Meteorological Agency — all-time national ranking, highest temperature
Confirmed that the ranking is built from each station’s own all-time first-place value, that an asterisk after a station name marks an observatory-class site while unmarked names are AMeDAS, and that Kumagaya carries the asterisk while Hatoyama does not; the rows down to 41.0 degrees, namely Isesaki in Gunma at 41.8 on 5 August 2025, Shizuoka at 41.4 on 6 August 2025, Hatoyama in Saitama at 41.4 on 5 August 2025, Kiryu in Gunma at 41.2 on 5 August 2025, Kaibara in Hyogo at 41.2 on 30 July 2025, Sakuma in Shizuoka at 41.1 on 23 July 2026, Hamamatsu at 41.1 on 17 August 2020, Kumagaya in Saitama at 41.1 on 23 July 2018, Maebashi in Gunma at 41.0 on 5 August 2025, Sano in Tochigi at 41.0 on 29 July 2024, Mino in Gifu at 41.0 on 8 August 2018, Kanayama in Gifu at 41.0 on 6 August 2018 and Egawasaki in Kochi at 41.0 on 12 August 2013; and that the next row below is 40.9.
https://www.data.jma.go.jp/stats/etrn/view/rankall.php
Japan Meteorological Agency — all-time first to tenth values, Hatoyama (AMeDAS), Saitama
Confirmed a highest daily maximum temperature of 41.4 degrees on 5 August 2025 in first place, 40.3 degrees on 30 August 2025 in second, and a statistical period running from December 1977, with no data-shortage symbol on the first-place value.
https://www.data.jma.go.jp/stats/etrn/view/rank_a.php?prec_no=43&block_no=1232
Japan Meteorological Agency — all-time first to tenth values, Kumagaya, Saitama
Confirmed a highest daily maximum temperature of 41.1 degrees on 23 July 2018 in first place, 40.9 degrees on 16 August 2007 in second, and a statistical period running from December 1896, with no data-shortage symbol on the first-place value.
https://www.data.jma.go.jp/stats/etrn/view/rank_s.php?prec_no=43&block_no=47626
Japan Meteorological Agency — climate normals for Kumagaya, Saitama
Confirmed nineteen data columns, with a statistical period of 1991 to 2020 and 30 years of data for fifteen of them including snow days, 1991 to 2019 with 29 years for mean cloud amount, fog days and thunder days, and no statistical period with 0 years for global solar radiation; the monthly mean, mean daily maximum and mean daily minimum temperatures of 4.3, 9.8 and minus 0.4 degrees for January and 27.1, 32.3 and 23.3 degrees for August, with annual figures of 15.4, 20.7 and 11.0; annual precipitation of 1,305.8 millimetres with 198.2 in September and 30.9 in December; annual sunshine of 2,106.6 hours with 217.0 in January and 131.6 in September; annual mean relative humidity of 65 per cent with 52 in February and 76 in July; annual mean wind speed of 2.5 metres per second with north-west the most frequent direction in January, February, March, April and December and east in June, July, August and September; annual thunder days of 20.2 with 6.0 in August and 5.1 in July and annual fog days of 5.3, both carrying the at-sign; total snowfall depth of 16 centimetres for the year with 7 in January, 7 in February, 1 in March and 1 in December; a largest daily snowfall total of 8 centimetres for the year; maximum snow depth of 9 centimetres for the year with 5 in February and 4 in January; and annual snow days of 17.7 with 6.0 in January, 5.5 in February, 3.4 in March, 2.6 in December, 0.2 in April and 0.1 in November.
https://www.data.jma.go.jp/stats/etrn/view/nml_sfc_ym.php?prec_no=43&block_no=47626
Saitama City — outline of the city
Confirmed that the city is the prefectural capital in the south-east of Saitama Prefecture, that it grew from a post town on the Nakasendo, that six Shinkansen lines including the Tohoku and Joetsu lines meet JR and private lines there, that the city was created in May 2001 by the merger of the former Urawa, Omiya and Yono cities, that it became the thirteenth designated city in Japan on 1 April 2003, that it merged with the former Iwatsuki City on 1 April 2005, that Citizens’ Day is 1 May because the city government started on that date in 2001, that the city tree is the zelkova with the Hikawa Shrine approach in Omiya and the Route 463 avenue named as examples, that the city flower is the Siebold primrose whose wild habitat at Tajimagahara in Sakura Ward is designated a national special natural monument and is maintained by removing invasive plants and burning off grass, that the city flowering tree is the cherry, and that the city office is at Tokiwa 6-4-4 in Urawa Ward with office hours of 8:30 to 17:15 excluding Saturdays, Sundays, public holidays and the year-end and new-year period, with a note that some organisations and facilities keep different hours.
https://www.city.saitama.lg.jp/006/012/001/007/p006217.html
Saitama City — history of the city
Confirmed that the city was created on 1 May 2001 by the merger of Urawa, Omiya and Yono; that on 1 April 2003 Nishi, Kita, Omiya and Minuma wards were established in the former Omiya City area, Chuo ward in the former Yono City area and Sakura, Urawa, Minami and Midori wards in the former Urawa City area, making it the thirteenth designated city in Japan; that Ohara 6-chome and 7-chome of the former Urawa City area became part of Omiya Ward; and that on 1 April 2005 Iwatsuki City was absorbed and Iwatsuki Ward established.
https://www.city.saitama.lg.jp/006/012/001/007/p015749.html
The Railway Museum — use guide
Confirmed opening hours of 10:00 to 17:00 with last admission 16:30 and closure every Tuesday and over the year-end and new-year period; advance ticket prices up to the day before of 1,500 yen general, 500 yen for primary, junior high and high school students and 200 yen for children aged 3 and over not yet in school, with same-day prices of 1,600, 600 and 300 yen; the disability rate of 800, 300 and 150 yen covering the certificate holder and up to one carer, the acceptance of the Mirairo ID app home screen, and the instruction to come directly to the entrance counter; the annual pass at 6,200, 2,500 and 1,000 yen, valid only for the person who signs it, with a note that a limited Shinkalion-illustration premium version is priced differently; the weekday afternoon pass at 4,800, 2,000 and 800 yen, usable only from 12:00 on weekdays, valid one year from purchase with the expiry moved back to the preceding weekday from 12:00 when the final day falls on a weekend, holiday or closing day; online advance sales without membership registration; advance sales at Seven-Eleven, Lawson and Ministop; experience-booking tickets for the mini driving train and the E5, D51 and conductor simulators sold through Seven Ticket only; the museum ticket machine selling same-day tickets from 10:00 on every open day with payment by transport IC card or cash; accessible parking in the P3 car park at 1,000 yen per car per day in a limited number of spaces with no reservations and no discount on presentation of a certificate; and that a sentence saying wheelchair lending is currently suspended is present only inside an HTML comment and is not displayed.
https://www.railway-museum.jp/information/
The Railway Museum — group use guide
Confirmed that the group scale applies from 20 or more paying visitors, at 1,200 yen general, 400 yen for primary, junior high and high school students and 160 yen for children aged 3 and over not yet in school, against individual figures of 1,600, 600 and 300; that school parties using the museum as part of school education receive the group scale with fewer than 20 paying visitors; that the opening bullet lists tour-company couriers and guides, coach drivers and teaching staff on school-education visits as admitted free while the note under the price table lists only the couriers and the teaching staff; and that the disability rate and the group rate are not applied together.
https://www.railway-museum.jp/information/group.html
Last updated: October 2026
