Monthly climate averages for Keystone, United States. Based on 10-year ERA5 reanalysis data.
Cfa Humid Subtropical
Climate OverviewKeystone, United States in May has hot conditions, with highs reaching 29°C (84°F) and afternoons the warmest part of the day. Rain falls on about 10 days this month. Sea temperature reaches 28°C (82°F).
This month falls at the end of Spring.
Temperatures remain fairly steady throughout May, with daily highs around 29°C (84°F).
May sees fairly even rainfall, totalling about 90 mm across the month.
The warmest days tend to fall around the 31th, averaging 30.3°C (87°F).
Compared to April, this month is about 2°C warmer with 3 more rainy days.
Daily averages based on historical data (2016–2025)
Daytime temperatures around 29°C (84°F) are ideal for full-day outdoor exploration.
Rain usually comes in shorter passing showers rather than all-day rain.
1 of the last 5 yearly records were warmer than this month's long-run average.
| Month | Temp | Feels Like | Rain | Sun | Humidity | UV | Status | Details |
|---|---|---|---|---|---|---|---|---|
| January | 19°C / 12°C | 19°C / 10°C | 6days (62 mm) Good | 8h Good | 73% Muggy | 4.6 Moderate | Good | View Details |
| February best | 22°C / 15°C | 23°C / 15°C | 6days (62 mm) Good | 8.9h Good | 78% Humid | 5.8 High | Excellent | View Details |
| March best | 24°C / 17°C | 25°C / 16°C | 6days (38 mm) Good | 9.7h Good | 72% Muggy | 7.2 Very High | Excellent | View Details |
| April best | 27°C / 19°C | 29°C / 20°C | 7days (58 mm) Good | 10.8h Excellent | 69% Muggy | 8.2 Very High | Excellent | View Details |
| May | 29°C / 22°C | 33°C / 24°C | 10days (89 mm) Wet | 11.4h Excellent | 71% Muggy | 8.5 Very High | Good | View Details |
| June | 30°C / 25°C | 35°C / 29°C | 20days (162 mm) Wet | 10.9h Excellent | 79% Humid | 8.4 Very High | Wet | View Details |
| July | 31°C / 25°C | 37°C / 30°C | 24days (199 mm) Wet | 10.5h Excellent | 81% Humid | 8.3 Very High | Wet | View Details |
| August | 30°C / 26°C | 37°C / 30°C | 23days (190 mm) Wet | 9.8h Good | 82% Humid | 8 Very High | Wet | View Details |
| September | 30°C / 24°C | 35°C / 28°C | 18days (170 mm) Wet | 9.6h Good | 81% Humid | 7.4 Very High | Wet | View Details |
| October | 27°C / 22°C | 30°C / 23°C | 8days (73 mm) Wet | 9.5h Good | 76% Humid | 6.1 High | Excellent | View Details |
| November best | 24°C / 17°C | 25°C / 17°C | 5days (36 mm) Good | 8.4h Good | 74% Muggy | 5 Moderate | Excellent | View Details |
| December best | 22°C / 15°C | 22°C / 14°C | 6days (53 mm) Good | 7.9h Good | 77% Humid | 4.3 Moderate | Excellent | View Details |
Summer clothing like shorts, t-shirts, and sundresses will be comfortable. Bring a light cardigan for air-conditioned spaces.
A waterproof jacket or compact umbrella is recommended for occasional showers.
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