May
May · October · June
71climate match
Japan · 1991–2020
Best time to visit
Iwase.
May leads for comfortable weather in Iwase: typically 23.6°C by day, 12.7°C at night, with 150 mm of rain. Based on measured 1991–2020 NOAA station history.
Best comfortMay
Typical high23.6°C
Typical low12.7°C
Rain in May150 mm
July
July · August · September
48climate match
November
November · April · May
68climate match
The weakest month is January, scoring 17 against May’s 71 — days reach only 8.7°C, 15° below the 24°C the score treats as ideal, and nights drop to -3°C.
Month by month
The whole year,
without the guesswork.
The bars show the comfort score. Day and night temperatures come from daily observed highs and lows; rain is the historical monthly estimate.
Jan
178.7° / -3°
Feb
199.8° / -2.1°
Mar
2813.5° / 1.5°
Apr
4819° / 7°
May
7123.6° / 12.7°
Jun
4926.2° / 17.1°
Jul
3029.7° / 21.2°
Aug
2931.1° / 22.4°
Sep
4427.2° / 18.8°
Oct
5021.5° / 12°
Nov
4716° / 5.1°
Dec
2510.8° / -0.5°
| Month | Day | Night | Rain | Wet days | Daylight | Comfort | Coverage |
|---|---|---|---|---|---|---|---|
| January | 8.7°C | -3°C | 28 mm | 2.8 | 9 h 56 | 17 | Good coverage |
| February | 9.8°C | -2.1°C | 39 mm | 5.6 | 10 h 48 | 19 | Good coverage |
| March | 13.5°C | 1.5°C | 88 mm | 8.8 | 11 h 51 | 28 | Good coverage |
| April | 19°C | 7°C | 135 mm | 10.7 | 13 h 04 | 48 | Good coverage |
| May | 23.6°C | 12.7°C | 150 mm | 10.9 | 14 h 05 | 71 | Good coverage |
| June | 26.2°C | 17.1°C | 235 mm | 16.5 | 14 h 37 | 49 | Good coverage |
| July | 29.7°C | 21.2°C | 236 mm | 16 | 14 h 24 | 30 | Good coverage |
| August | 31.1°C | 22.4°C | 214 mm | 13.1 | 13 h 32 | 29 | Good coverage |
| September | 27.2°C | 18.8°C | 239 mm | 13.8 | 12 h 22 | 44 | Good coverage |
| October | 21.5°C | 12°C | 243 mm | 10.6 | 11 h 12 | 50 | Good coverage |
| November | 16°C | 5.1°C | 76 mm | 6.6 | 10 h 11 | 47 | Good coverage |
| December | 10.8°C | -0.5°C | 49 mm | 4.8 | 9 h 42 | 25 | Good coverage |
What has changed
Iwase runs +1.9°C
on the 1961–1990 baseline.
Each bar compares the 2011–2025 daytime average for that month against the same month in 1961–1990, measured at the same station. Months where the older record is too thin to compare are left blank.
Jan
+1.0
Feb
+1.6
Mar
+3.0
Apr
+2.0
May
+2.2
Jun
+2.5
Jul
+2.9
Aug
+1.7
Sep
+2.4
Oct
+1.4
Nov
+1.2
Dec
+0.6
| Month | Record high | Record low | Wettest day | Wettest / driest month | Years |
|---|---|---|---|---|---|
| January | 20.9°C27 Jan 1969 | -12.4°C25 Jan 1963 | 67 mm27 Jan 2002 | 112 mm2002 · driest 0 mm in 2019 | 75 |
| February | 24.6°C11 Feb 1962 | -13.3°C20 Feb 1952 | 70 mm9 Feb 1985 | 140 mm1972 · driest 0 mm in 2026 | 75 |
| March | 27.2°C19 Mar 2013 | -10.1°C6 Mar 1970 | 61 mm30 Mar 1977 | 170 mm2021 · driest 10 mm in 1973 | 75 |
| April | 30.1°C28 Apr 2015 | -4.7°C6 Apr 1965 | 92 mm18 Apr 2020 | 240 mm1998 · driest 0 mm in 2025 | 75 |
| May | 34.4°C26 May 2019 | -0.2°C3 May 1953 | 135 mm4 May 2012 | 343 mm1965 · driest 0 mm in 2025 | 74 |
| June | 37.6°C25 Jun 2022 | 7.7°C3 Jun 1952 | 179 mm28 Jun 1966 | 449 mm2014 · driest 0 mm in 2025 | 74 |
| July | 38.7°C5 Jul 1997 | 10.3°C3 Jul 1976 | 159 mm28 Jul 1997 | 374 mm2011 · driest 0 mm in 2025 | 75 |
| August | 37.5°C15 Aug 1996 | 12.3°C20 Aug 1956 | 219 mm7 Aug 1957 | 518 mm2008 · driest 0 mm in 2025 | 73 |
| September | 36.5°C2 Sep 2000 | 6.3°C24 Sep 1963 | 241 mm10 Sep 2015 | 496 mm1958 · driest 0 mm in 2025 | 73 |
| October | 33.5°C1 Oct 2018 | 0.4°C19 Oct 1957 | 266 mm12 Oct 2019 | 527 mm2019 · driest 0 mm in 1997 | 74 |
| November | 25.1°C5 Nov 1990 | -5.9°C29 Nov 1969 | 90 mm7 Nov 1975 | 192 mm1975 · driest 0 mm in 2025 | 74 |
| December | 24.7°C5 Dec 2004 | -9.6°C31 Dec 1967 | 131 mm27 Dec 2006 | 172 mm1968 · driest 0 mm in 1981 | 74 |
| Month | Days 25°C+ | Days 30°C+ | Frost nights | Heavy rain (10 mm+) |
|---|---|---|---|---|
| January | 0 | 0 | 15 | 1 |
| February | 0 | 0 | 13 | <1 |
| March | <1 | 0 | 6 | 3 |
| April | 2 | 0 | <1 | 4 |
| May | 11 | <1 | 0 | 4 |
| June | 18 | 4 | 0 | 5 |
| July | 25 | 15 | 0 | 5 |
| August | 27 | 20 | 0 | 4 |
| September | 20 | 7 | 0 | 6 |
| October | 4 | <1 | 0 | 4 |
| November | 0 | 0 | 1 | 2 |
| December | 0 | 0 | 10 | 1 |
| Month | Warm & dry days | Wet days | Washouts | Week with 3+ wet days | Daytime mean has ranged |
|---|---|---|---|---|---|
| January | <1% | 12% | 4% | 6% | 7.0–9.8°C |
| February | <1% | 21% | 5% | 19% | 7.4–11.3°C |
| March | 4% | 29% | 11% | 31% | 11.0–14.7°C |
| April | 26% | 36% | 15% | 44% | 16.5–20.3°C |
| May | 54% | 38% | 16% | 47% | 21.0–24.5°C |
| June | 50% | 49% | 21% | 68% | 23.0–27.4°C |
| July | 53% | 47% | 19% | 60% | 26.2–31.6°C |
| August | 61% | 39% | 17% | 51% | 28.7–32.8°C |
| September | 54% | 46% | 22% | 62% | 24.3–28.4°C |
| October | 44% | 34% | 16% | 34% | 19.5–22.3°C |
| November | 9% | 21% | 8% | 17% | 14.3–17.3°C |
| December | <1% | 13% | 4% | 6% | 9.2–12.1°C |
A warm and dry day reaches 20°C with under 1 mm of rain; a wet day gets 1 mm or more; a washout gets 10 mm or more. The week column is the share of seven-day stretches in that month, across the station’s whole daily record, that contained three or more wet days — the odds a week-long trip is rained on repeatedly, counted rather than modelled. The last column is the 10th to 90th percentile of that month’s daytime average across individual years: a narrow band means the average is what you will get, a wide one means the average is a midpoint between years that felt quite different.
The evidence behind this page
Nearby, measured,
and named.
- Place identity
- GeoNames 2112521
- NOAA station
- JA000047615 · UTSUNOMIYA
- Station distance
- 30.5 km from the place centre
- Climate period
- 1991–2020
- Minimum month coverage
- 17 usable years
- Daylight
- Calculated from latitude 36.35°, mid-month, sunrise to sunset including refraction. Not a station measurement.
- Important limit
- Historical climate is not a forecast. Nearby stations can miss mountains, coasts, and local microclimates.