10-day outlook — past day 10 this is an outlook from the end of the GFS run: expect differences of several degrees.
Morning
Partly cloudy
14°
Feels like 14°
Wind↑ NW 10 km/h
Humidity 40 %
Evening
Mainly clear
16°
Feels like 16°
Wind↑ NE 5 km/h
Humidity 39 %
11-day outlook — past day 10 this is an outlook from the end of the GFS run: expect differences of several degrees.
Morning
Partly cloudy
15°
Feels like 15°
Wind↑ N 8 km/h
Humidity 56 %
Evening
Mainly clear
15°
Feels like 15°
Wind↑ ENE 12 km/h
Gusts20 km/h
Humidity 64 %
12-day outlook — past day 10 this is an outlook from the end of the GFS run: expect differences of several degrees.
Morning
Clear sky
15°
Feels like 15°
Wind↑ N 9 km/h
Humidity 55 %
Evening
Clear sky
15°
Feels like 15°
Wind↑ ESE 9 km/h
Gusts17 km/h
Humidity 50 %
13-day outlook — past day 10 this is an outlook from the end of the GFS run: expect differences of several degrees.
Morning
Clear sky
15°
Feels like 15°
Wind↑ N 5 km/h
Humidity 50 %
Evening
Partly cloudy
17°
Feels like 17°
Wind↑ SE 6 km/h
Gusts13 km/h
Humidity 56 %
Koshigaya forecast in charts · next 7 days
The week ahead: highs and lows
≈ A week close to the usual temperatures
Highs Lows Usual for the season (1991–2020 average)
Hourly detail
Temperature (°C) Rain (mm) Wind (km/h)
Koshigaya climate: what a normal year looks like
The hottest stretch is August, when afternoons average 31 °C; the coldest is January, when nights average 0 °C. Between those two months the average temperature changes by 23 °C.
Typical highs of 30 °C or more are reached in August only, at 31 °C.
From 14 h 35 min of daylight in late June to 9 h 43 min in late December.
A normal year brings roughly 1,450 mm of rain — more than 74% of the towns of 20,000+ people we compared it with.
Forecast highs for the coming week average 19 °C, 2 °C cooler than a normal October (21 °C).
30-year averages (1991–2020)
Month
Typical high
Typical low
Rainfall
Jan
9 °C
0 °C
65 mm
Feb
10 °C
2 °C
64 mm
Mar
13 °C
5 °C
107 mm
Apr
18 °C
10 °C
112 mm
May
23 °C
15 °C
134 mm
Jun
26 °C
19 °C
162 mm
Jul
30 °C
23 °C
158 mm
Aug
31 °C
25 °C
123 mm
Sep
27 °C
21 °C
184 mm
Oct
21 °C
15 °C
200 mm
Nov
17 °C
8 °C
87 mm
Dec
12 °C
3 °C
57 mm
Whole year
20 °C
12 °C
1,450 mm
Source: our own processing of the ERA5 reanalysis (Copernicus/ECMWF) for 35.89° N, 139.79° E, 1991–2020. ERA5 averages over a 0.25° grid (about 25 km): hills, a coastline or the heat of the city itself can shift local values by a degree or two.
Air you breathe in Koshigaya: pollution and pollen
1/6
Good
European Air Quality Index (EAQI), from Copernicus CAMS
PM2.55µg/m³
PM105µg/m³
Copernicus CAMS model, updated several times a day.
Rain radar around Koshigaya
Rain observed over the last two hours by official weather radars around Koshigaya, followed by the radar forecast for the next hour where the weather service provides one.
Rain radarLast two hours, then forecast where available · drag the timeline
No open weather radar covers Koshigaya yet: the map shows our hour-by-hour rain forecast (ICON, GFS).
Moon over Koshigaya
Waning gibbous
79 % illuminated · 19.3 days
Rise 14:57 Set 05:29
Sat31/1069%
Sun1/1159%
Mon2/1149%Last quarter
Tue3/1138%
Wed4/1128%
Thu5/1119%
Fri6/1112%
Sat7/116%
Sun8/112%
Mon9/110%
Tue10/111%New moon
Wed11/113%
Moonrise and moonset in local time (Asia/Tokyo); phase and lit fraction from a synodic calculation.
Look up a past day in Koshigaya
Curious about the weather in Koshigaya on a given day? Choose a date: we read it from the ERA5 reanalysis (ECMWF / Copernicus C3S), which runs until about a week ago.
Koshigaya weather at a glance
This page gathers everything about the weather in Koshigaya, Saitama: conditions now, the forecast for each part of the day and the trend for the coming week. At the moment the sky is “partly cloudy”, it is 15 °C (feels like 15 °C) and the wind blows at 6 km/h.
Expected range today: 12 °C to 20 °C and a dry sky. The forecast comes from the AtmoAtlas engine, which combines ECMWF-AIFS, NOAA GFS and DWD ICON, adjusts cloud cover with METAR reports and uses convective energy (CAPE) to flag storms.
Use the Koshigaya forecast in your own website or app: one JSON call returns weather, air quality, tides and sun and moon times. The free key needs no card.
