Monthly Climate
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Best time to visit Iwaki

May is the best time to visit Iwaki for general sightseeing, with average highs of 20 °C and about 13 wet days. The comfortable season runs roughly May to June. The sea stays above 20 °C from July to October.

It depends what you are going for

One month rarely wins on everything. These are the best months on each measure taken on its own.

If you want Best month On that measure
Sightseeing and walking May comfort 82/100
A beach holiday August sea 24 °C
The least cloud December 41 % average cloud cover
The least rain February 61 mm
Warmth August 28 °C
Cooler weather January 6.8 °C

Ranked by comfort

# Month Comfort / 100 Avg high Wet days Beach
1 May 82 20 °C 13 33
2 October 82 20 °C 12 48
3 June 78 23 °C 16 48
4 September 75 25 °C 15 69
5 November 69 15 °C 9 32
6 April 66 16 °C 12 12
7 July 65 26 °C 17 66
8 August 62 28 °C 16 74
9 December 49 9.4 °C 8 23
10 March 46 11 °C 12 7
11 January 39 6.8 °C 7 17
12 February 39 7.3 °C 8 15

For a beach holiday

August scores highest, with a sea temperature of 24 °C and air temperatures around 28 °C. The sea is above 20 °C from July to October.

Month Sea Air Sunshine Beach score
January 14 °C 6.8 °C 42 % 17
February 12 °C 7.3 °C 49 % 15
March 12 °C 11 °C 56 % 7
April 14 °C 16 °C 60 % 12
May 16 °C 20 °C 67 % 33
June 19 °C 23 °C 79 % 48
July 21 °C 26 °C 79 % 66
August 24 °C 28 °C 72 % 74
September 23 °C 25 °C 71 % 69
October 20 °C 20 °C 62 % 48
November 18 °C 15 °C 50 % 32
December 16 °C 9.4 °C 41 % 23

When to think twice

February scores lowest with about 8 wet days and highs near 7.3 °C. That does not make it a bad month — it depends entirely on what you are travelling for. The numbers are all here; the judgement is yours.

The full year

Month Avg high Rainfall Cloud
January 6.8 °C 64 mm 42 %
February 7.3 °C 61 mm 49 %
March 10.6 °C 112 mm 56 %
April 15.5 °C 124 mm 60 %
May 19.9 °C 138 mm 67 %
June 22.7 °C 146 mm 79 %
July 26.1 °C 191 mm 79 %
August 27.5 °C 152 mm 72 %
September 24.5 °C 194 mm 71 %
October 19.5 °C 187 mm 62 %
November 14.6 °C 93 mm 50 %
December 9.4 °C 61 mm 41 %

Data sources and method

Normal period
1991–2020
Dataset version
era5-1991-2020-scores1.1
Last processed

Measured values come from ERA5 reanalysis and are reproduced unchanged. Calculated by us: comfort score, beach score, season boundaries. Full formulas are on the methodology page.

Contains modified Copernicus Climate Change Service information 2026. Neither the European Commission nor ECMWF is responsible for any use that may be made of the Copernicus information or data it contains.