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Williams Bay climate
Typical historical weather for Williams Bay, United States, averaged across 10 years of hourly climate data. Pick a date for a specific day.
Data last updated: 31 December 2025
Want today's actual conditions instead? See the current forecast for Williams Bay. Planning a garden? See the gardening & growing season planner. Or browse the 365-day climate calendar.
Annual average
10°C
across all months
Warmest month
27.9°C
Jul average high
Coolest month
-8.6°C
Jan average low
Annual rainfall
995mm
total per year
Williams Bay is typically hottest in July and coolest in January, a swing of about 36.5°C across the year. About 32% of annual rainfall falls in the three wettest months (May is typically wettest, February driest).
Monthly averages
Average daily high/low temperature (band) and monthly rainfall (bars).
| Month | Avg high | Avg low | Rainfall | Wet days | Humidity | Wind | Cloud | Solar |
|---|---|---|---|---|---|---|---|---|
| Jan | -1.5°C · record 3.2°C–13.8°C | -8.6°C · record -33.3°C–-18.3°C | 59mm | 9 | 77% | 3.7 m/s | 71% | 1.9 kWh/m² |
| Feb | 1.5°C · record 7.2°C–22.4°C | -7.6°C · record -28.1°C–-12.5°C | 49mm | 8 | 70% | 3.9 m/s | 64% | 3 kWh/m² |
| Mar | 8.3°C · record 13.9°C–26.2°C | -1.1°C · record -22.4°C–-5.1°C | 88mm | 11 | 67% | 3.9 m/s | 66% | 3.9 kWh/m² |
| Apr | 13.7°C · record 24.8°C–28.2°C | 3.6°C · record -8.5°C–-1.1°C | 109mm | 14 | 64% | 4 m/s | 66% | 4.9 kWh/m² |
| May | 20.6°C · record 27.8°C–34°C | 10.3°C · record -1.3°C–6.2°C | 118mm | 13 | 65% | 3.4 m/s | 63% | 5.7 kWh/m² |
| Jun | 26.6°C · record 31.3°C–36°C | 16.4°C · record 6.1°C–10.2°C | 95mm | 12 | 66% | 3.2 m/s | 54% | 6.5 kWh/m² |
| Jul | 27.9°C · record 31.2°C–33.8°C | 18.6°C · record 9.9°C–15.4°C | 94mm | 11 | 71% | 2.7 m/s | 53% | 6.3 kWh/m² |
| Aug | 26.8°C · record 29.1°C–35.5°C | 17.3°C · record 8.2°C–12.7°C | 92mm | 11 | 74% | 2.7 m/s | 51% | 5.5 kWh/m² |
| Sep | 23.9°C · record 28.8°C–33.2°C | 13.9°C · record 2.4°C–9.7°C | 93mm | 9 | 74% | 3.1 m/s | 49% | 4.4 kWh/m² |
| Oct | 16.4°C · record 25.7°C–30°C | 7.1°C · record -5.3°C–1.5°C | 91mm | 11 | 72% | 3.7 m/s | 56% | 3 kWh/m² |
| Nov | 8.1°C · record 10.6°C–24°C | 0°C · record -15.8°C–-4.3°C | 52mm | 7 | 72% | 3.8 m/s | 61% | 2.1 kWh/m² |
| Dec | 1.9°C · record 8.6°C–18.5°C | -5°C · record -24.4°C–-9.8°C | 55mm | 8 | 76% | 3.8 m/s | 71% | 1.6 kWh/m² |
"Avg high"/"Avg low" is the mean daily high/low for that month, averaged across every year on file. The "record" figure alongside it is a different statistic — the single hottest (or coldest) hour ever recorded during that month across all years — so it can sit above or below the average and does not describe the average's year-to-year spread. A "wet day" is any day with at least 1.0mm of rain.
Year to year
Annual average temperature, 2016–2025.
Across these 10 years, the annual average has moved by about +0.7°C per decade. That’s a short window for a reliable long-term climate trend — treat it as indicative, not definitive.
Annual rainfall has moved by about -290.03mm per decade over the same period.
2025 (the most recent year on file) averaged 9.8°C, below the 9-year baseline of 10.1°C by 0.4 standard deviations.
Typical extremes per year
Rainy days
124.9 days
≥1.0mm rain
Heavy rain days
9.2 days
≥20mm rain
Extreme heat days
0 days
daily high ≥40°C
Frost days
118.6 days
daily low ≤0°C
Averaged across 10 years on file. Thresholds match PastClimate's data pipeline definitions — see data & sources.
Records on file
Ranked across 10 years of data currently on file (2016–2025).
Hottest day
36°C
21 June 2022
2022 was 1.01 SD below the 9-year average that year
Coldest day
-33.3°C
31 January 2019
2019 was 2.06 SD below the 9-year average that year
Wettest day
68.9mm
11 September 2022
2022 was 1.01 SD below the 9-year average that year
Windiest day
9.1m/s
16 March 2016
2016 was 0.55 SD above the 9-year average that year
See the detail: Williams Bay on 11 September 2022.
Nearby cities
Frequently asked questions about Williams Bay's climate
What is the hottest month in Williams Bay?
July is typically the warmest month in Williams Bay, with an average high of 27.9°C. January is typically the coolest, averaging -8.6°C overnight.
How much does it rain in Williams Bay?
Williams Bay gets about 995mm of rain a year on average, with roughly 32% of it falling in the three wettest months (May is typically the wettest, February the driest).
How many extremely hot or cold days does Williams Bay have?
On average, Williams Bay sees about 0 day(s) a year at or above 40°C and about 118.6 day(s) at or below 0°C, based on 10 years of data.
Is Williams Bay getting warmer?
Across the 10 years on file (2016–2025), the annual average temperature has moved by about +0.71°C per decade. That's a short window for a reliable long-term climate trend — treat it as indicative, not definitive.
What is the hottest day on record for Williams Bay?
The hottest day on file is 21 June 2022 at 36°C, out of 10 year(s) searched.
Data & provenance
↓ Download monthly CSVData source & coverage — ERA5 reanalysis, 2016–2025 (10 years)details
- Source
- ERA5 reanalysis, accessed via the Copernicus Climate Change Service (C3S) Climate Data Store
- Data type
- Reanalysis — a physically consistent reconstruction combining a forecast model with historical observations, not a live station reading or a forecast
- Coverage
- 2016–2025 (10 years) for United States
- Location
- Williams Bay — 42.500°, -88.500°, ERA5 grid cell center, 9.3 km from requested point
- Time zone
- America/Chicago
- What's shown here
- Monthly and annual averages, and dated extreme-value records, derived from an hourly base record.
- Spatial resolution
- 0.25° (~25 km) distributed grid — ERA5's native model resolution is finer; this is the publicly distributed regridded product
- Version / refreshed
- Methodology v2026.07 · data last refreshed December 31, 2025
- Limitations
- A model reconstruction, not a station observation — hyper-local extremes (a single storm cell, an urban heat pocket) can differ from a nearby gauge. See the full methodology.
- Attribution
- Generated using Copernicus Climate Change Service information
Cite this data
PastClimate (2026-07-20). Historical climate data for Williams Bay, United States (42.50°N, 88.50°W), derived from ERA5 (Hersbach et al., 2023, Copernicus Climate Change Service). Retrieved from https://www.pastclimate.com/
PastClimate. (2026). Historical climate data for Williams Bay, United States [Data set]. Derived from ERA5 (Copernicus Climate Change Service). Retrieved July 20, 2026, from https://www.pastclimate.com/
"Historical Climate Data for Williams Bay, United States." PastClimate, derived from ERA5 (Copernicus Climate Change Service), July 20, 2026, www.pastclimate.com.
@misc{pastclimate,
author = {PastClimate},
title = {Historical climate data for Williams Bay, United States},
year = {2026},
note = {Derived from ERA5 (Hersbach et al., 2023), Copernicus Climate Change Service. Accessed 2026-07-20},
url = {https://www.pastclimate.com/}
}Notice something wrong with this data? Report a data issue.