Waterloo, United States experiences average highs of 15°C (59°F) and lows of 6°C (43°F) throughout the year. Rainfall is moderate, averaging about 9 rainy days per month. Sunshine is abundant, averaging about 9 hours per day. Average highs have stayed broadly stable across the available records.
Waterloo, United States Weather & Climate 2026
Monthly climate averages for Waterloo, United States. Based on 10-year ERA5 reanalysis data.
Climate Overview
Drier season: Jan–Dec 
Wetter season: Mar–Jul At-a-Glance Climate Summary
Live Weather & Air Quality
Key figures
Climate Score
5.3/10
Best: May, June, July, August, September
UV Index
5
Low
Temperature 15°C / 6°C
Feels Like 13°C / 3°C
Rainy Days 9
Rainfall 84 mm
Sunshine 9 h
Humidity 70%
Wind Speed 22 km/h
Dew Point 5°C
Snow Days 5 days
Frost Days 17 days
Hottest Month
28°C
July
Avg Low19°C
Rain10days
Coldest Month
-10°C
January
Avg High-2°C
Rain7days
Driest Month
6days
February
Avg High1°C
Avg Low-9°C
Windiest Month
27 km/h
April (Gusts 50)
Worst Time to Visit
Consider avoiding January, February, March, December due to very cold temperatures.
Sun Position
Sunrise 05:33
Daylight 15.3h
Sunset 20:50
Live conditions—
Waterloo on the map · live conditions
Waterloo, United States
- Continent
- Americas
- Country
- United States
- City
- Waterloo
- Population
- 68.5K
- Elevation
- 261 m
- Coordinates
- 42.49°, -92.34°
Seasonal Breakdown
Spring
Mar–May
Avg High 15°C
Avg Low 5°C
Rain 11 days/mo
1/3 best months
Summer
Jun–Aug
Avg High 28°C
Avg Low 18°C
Rain 10 days/mo
3/3 best months
Autumn
Sep–Nov
Avg High 17°C
Avg Low 8°C
Rain 8 days/mo
1/3 best months
Winter
Dec–Feb
Avg High 0°C
Avg Low -8°C
Rain 6 days/mo
Climate Charts
Based on historical averages (2016–2025)
Monthly Temperatures
HighLowShaded bands show the typical range across the available yearly records.
Line chart showing monthly temperatures. Jan: -2°C / -10°C . Feb: 1°C / -9°C . Mar: 9°C / -1°C . Apr: 15°C / 4°C . May: 22°C / 11°C . Jun: 28°C / 18°C . Jul: 28°C / 19°C . Aug: 27°C / 18°C . Sep: 25°C / 15°C . Oct: 17°C / 8°C . Nov: 9°C / 0°C . Dec: 2°C / -6°C .
Monthly Rainfall
Rainfall
Bar chart showing monthly rainfall. Jan: 41 mm. Feb: 37 mm. Mar: 81 mm. Apr: 102 mm. May: 140 mm. Jun: 118 mm. Jul: 115 mm. Aug: 92 mm. Sep: 99 mm. Oct: 96 mm. Nov: 51 mm. Dec: 39 mm.
Monthly Humidity
Humidity
Line chart showing monthly humidity. Jan: 76%. Feb: 71%. Mar: 66%. Apr: 64%. May: 67%. Jun: 68%. Jul: 75%. Aug: 73%. Sep: 69%. Oct: 65%. Nov: 69%. Dec: 72%.
Monthly Wind Speed
Wind SpeedGusts
Bar chart showing monthly wind speed. Jan: 22 km/h . Feb: 25 km/h . Mar: 25 km/h . Apr: 27 km/h . May: 22 km/h . Jun: 21 km/h . Jul: 18 km/h . Aug: 18 km/h . Sep: 20 km/h . Oct: 24 km/h . Nov: 23 km/h . Dec: 23 km/h .
Sunshine
Sunshine
Sunshine: Jan: 6h. Feb: 7h. Mar: 8h. Apr: 9h. May: 10h. Jun: 12h. Jul: 12h. Aug: 11h. Sep: 10h. Oct: 8h. Nov: 6h. Dec: 5h.
UV Index
UV Index
Bar chart showing monthly UV index. Jan: UV 2. Feb: UV 4. Mar: UV 4. Apr: UV 5. May: UV 7. Jun: UV 7. Jul: UV 7. Aug: UV 7. Sep: UV 6. Oct: UV 4. Nov: UV 3. Dec: UV 2.
Monthly Daylight Hours
Daylight12h reference
Monthly Dew Point & Comfort
Dew Point Dry Comfortable Humid Muggy Oppressive
Snow Days
Snow DaysSnowfall
Snow Days: Jan: 9 days. Feb: 8 days. Mar: 4 days. Apr: 2 days. May: 0 days. Jun: 0 days. Jul: 0 days. Aug: 0 days. Sep: 0 days. Oct: 1 days. Nov: 3 days. Dec: 8 days.
Climate Trends
Average highs have stayed broadly stable across the available records. Average rainfall is trending drier by about 12 mm.
2016 to 2025
Avg high Avg rainfall
Climate summary
| Last 12 months | All years | |
|---|---|---|
| Hottest month | Jul 2025 · 29°C | Jul · 28°C |
| Coldest month | Dec 2025 · -11°C | Jan · -10°C |
| Wettest month | Jul 2025 · 238 mm | May · 140 mm |
| Windiest month | Mar 2025 · 28 km/h | Apr · 27 km/h |
Month-by-Month Weather Table
January
Poor 
February
Poor March
Poor April
Fair May best
Good June best
Excellent July best
Excellent August best
Excellent September best
Excellent October
Fair November
Poor December
Poor | Month | Temp | Feels Like | Rain | Sun | Humidity | UV | Status | Details |
|---|---|---|---|---|---|---|---|---|
| January | -2°C / -10°C | -7°C / -16°C | 7days (41 mm) Good | 5.6h Fair | 76% Humid | 2.4 Moderate | Poor | View Details |
| February | 1°C / -9°C | -4°C / -15°C | 6days (37 mm) Good | 7.4h Good | 71% Muggy | 3.6 Moderate | Poor | View Details |
| March | 9°C / -1°C | 5°C / -6°C | 10days (81 mm) Wet | 7.9h Good | 66% Muggy | 4.4 Moderate | Poor | View Details |
| April | 15°C / 4°C | 12°C / 0°C | 12days (102 mm) Wet | 8.8h Good | 64% Muggy | 5.3 High | Fair | View Details |
| May best | 22°C / 11°C | 21°C / 9°C | 12days (140 mm) Wet | 9.9h Good | 67% Muggy | 6.8 High | Good | View Details |
| June best | 28°C / 18°C | 29°C / 17°C | 11days (118 mm) Wet | 12h Excellent | 68% Muggy | 7 High | Excellent | View Details |
| July best | 28°C / 19°C | 31°C / 20°C | 10days (115 mm) Wet | 12.1h Excellent | 75% Muggy | 7.1 Very High | Excellent | View Details |
| August best | 27°C / 18°C | 29°C / 19°C | 9days (92 mm) Wet | 11.3h Excellent | 73% Muggy | 6.6 High | Excellent | View Details |
| September best | 25°C / 15°C | 25°C / 14°C | 9days (99 mm) Wet | 9.7h Good | 69% Muggy | 5.5 High | Excellent | View Details |
| October | 17°C / 8°C | 14°C / 5°C | 9days (96 mm) Wet | 7.5h Good | 65% Muggy | 3.9 Moderate | Fair | View Details |
| November | 9°C / 0°C | 5°C / -4°C | 6days (51 mm) Good | 6.4h Fair | 69% Muggy | 2.6 Moderate | Poor | View Details |
| December | 2°C / -6°C | -3°C / -11°C | 6days (39 mm) Good | 5.4h Fair | 72% Muggy | 2 Low | Poor | View Details |
Compare Nearby City Climates
Frequently Asked Questions
The best months to visit Waterloo are May, June, July, August, September, when temperatures are comfortable and rainfall is at its lowest. This is based on 10-year climate averages for Waterloo, scoring temperature, rainfall, humidity, and sunshine hours.
The hottest month in Waterloo is July, with average daytime highs of 28°C (83°F). Plan outdoor activities for early morning or late afternoon if visiting during this period.
The coldest month in Waterloo is January, with average overnight lows of -10°C (13°F). Pack warm layers and expect shorter daylight hours during this period.
The wettest month in Waterloo is May, averaging 140mm of precipitation across 12 rainy days. An umbrella or waterproof jacket is essential.
The rainy season in Waterloo runs through April, May, June, March, with the heaviest rainfall in April. Based on 10-year averages for Waterloo.
Waterloo receives approximately 104 sunshine hours per year. The sunniest month is July with around 12 hours. Based on climate data for Waterloo.
The least favorable months to visit Waterloo are January, February, March, December, primarily due to very cold temperatures. For the best conditions, consider May, June, July, August, September instead.
The annual average UV index in Waterloo is 5, classified as moderate. Standard sun protection (sunscreen, hat) is recommended during prolonged outdoor exposure.
Average humidity in Waterloo is 70%, classified as moderate. Humidity levels are generally comfortable and should not affect outdoor activities for most people.
Yes, Waterloo receives snow. Months with snowfall average 5 snow days and 10 cm (4 in) of accumulation, with about 17 frost days during winter.
Average wind speeds in Waterloo are 22 km/h (14 mph). The windiest month is April with peak winds reaching 27 km/h (17 mph) (gusts up to 50 km/h / 31 mph).
Waterloo averages 5 clear-sky days per month with overall cloud cover around 56%. The clearest skies occur in September.
The annual average dew point in Waterloo is 5°C (41°F), which feels dry and comfortable. Outdoor activities are comfortable year-round from a humidity standpoint.
Waterloo has a Hot-Summer Continental climate, classified as Dfa under the Köppen system. Continental climates experience extreme temperature ranges — hot summers and cold, snowy winters.
The 'feels like' temperature in Waterloo ranges from 3°C (37°F) to 13°C (55°F) on average. Wind chill makes winters feel noticeably colder than the actual temperature — layered clothing is recommended.
Yes, June is a great time to visit Waterloo. It earns a climate score of 8.4/10 with Excellent.
For June in Waterloo, pack Umbrella, Waterproof jacket, Breathable clothing, Sunscreen (SPF 30+), Sun hat. With average highs of 28°C (82°F) and 11 rainy days, these essentials will keep you comfortable.
Data Source
Climate data derived from ERA5 reanalysis (ECMWF), averaged over 2016–2025. Sea surface temperature from marine reanalysis data. Climate scores and seasonal estimates are computed by WorldStats.
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