Lewis and Clark County (Helena)
May
Weather in Lewis and Clark County, Montana for May 2026
Your guide to Lewis and Clark County weather in May - trends and predictions
In general, the average temperature in Lewis and Clark County at the beginning of May is 17.1 °F. As the month progressed, temperatures tended to significantly warm up, reaching an average of 23.9 °F by the end of May.
The climate of Lewis and Clark County in May is notably wet, with an average of 12 rainy days, and a total of 71.7 mm of precipitation.
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Temperatures
Rain 🌧️
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19
Dry days
12
Rainy days
0
Snow days
18°/4°
Temperatures
16 km/h
Avg max wind
58 %
Avg humidity
Lewis and Clark County Weather May
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Temperatures trend during May in Lewis and Clark County
See the weather trend as well as the moving average line
May weather in Lewis and Clark County day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| May 1 |  Sunny | 16° /1° | 0 mm | 5 | |
| May 2 | Sunny | 22° /2° | 0 mm | 6 | |
| May 3 | Sunny | 23° /3° | 0 mm | 6 | |
| May 4 |  Overcast | 17° /4° | 9.8 mm | 4 | |
| May 5 |  Moderate or heavy rain shower | 8° /1° | 13.3 mm | 2 | |
| May 6 | Overcast | 14° /-1° | 0 mm | 3 | |
| May 7 |  Cloudy | 20° /0° | 0 mm | 5 | |
| May 8 | Sunny | 21° /6° | 0 mm | 6 | |
| May 9 |  Partly cloudy | 24° /5° | 0 mm | 6 | |
| May 10 | Moderate rain at times | 28° /9° | 1.5 mm | 6 | |
| May 11 | Overcast | 24° /9° | 0 mm | 5 | |
| May 12 |  Patchy rain possible | 19° /7° | 1.8 mm | 4 | |
| May 13 | Moderate rain at times | 11° /5° | 4.5 mm | 3 | |
| May 14 | Moderate or heavy rain shower | 12° /5° | 17.2 mm | 3 | |
| May 15 | Moderate or heavy rain shower | 11° /4° | 11.3 mm | 3 | |
| May 16 | Overcast | 13° /2° | 0 mm | 3 | |
| May 17 | Overcast | 16° /2° | 0.5 mm | 4 | |
| May 18 | Patchy rain possible | 10° /6° | 3.9 mm | 3 | |
| May 19 | Partly cloudy | 14° /1° | 0 mm | 4 | |
| May 20 | Patchy rain possible | 14° /2° | 0.2 mm | 3 | |
| May 21 | Patchy rain possible | 14° /1° | 0.5 mm | 3 | |
| May 22 | Patchy rain possible | 15° /2° | 3.3 mm | 4 | |
| May 23 | Patchy rain possible | 17° /3° | 3.9 mm | 4 | |
| May 24 | Sunny | 18° /4° | 0 mm | 5 | |
| May 25 | Sunny | 22° /4° | 0 mm | 6 | |
| May 26 | Sunny | 24° /5° | 0 mm | 6 | |
| May 27 |  Thundery outbreaks possible | 20° /8° | 0 mm | 5 | |
| May 28 | Sunny | 22° /8° | 0 mm | 6 | |
| May 29 | Sunny | 27° /8° | 0 mm | 7 | |
| May 30 | Sunny | 22° /9° | 0 mm | 6 | |
| May 31 | Sunny | 30° /9° | 0 mm | 8 | |
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Important Notice
Our weather forecast for Lewis and Clark County in May is based on the analysis of historical data rather than real-time forecast models. While this provides a general overview, weather conditions can change. We recommend that you check the Lewis and Clark County forecast closer to your planned date for the most up-to-date weather information.
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Lewis and Clark County in May - FAQ
What are the expected maximum and minimum temperatures in Lewis and Clark County during May?
During May, expect a variety of temperatures with highs around 18° and lows near 4°, suitable for diverse activities and preferences.
How much rainfall should be expected in Lewis and Clark County during May?
Moderate rainfall is anticipated in Lewis and Clark County during May, with a total of 71.7 mm spread over approximately 12 days. Considering plans for rainy days is advisable.
What are the typical wind conditions in Lewis and Clark County during May?
The average wind speed in Lewis and Clark County during May is 16 km/h, suggesting breezy to windy conditions, depending on your activities.
May rainfall patterns in Lewis and Clark County
Explore the daily rainfall trends and prepare for Lewis and Clark Countys May weather 💧
Typically, Lewis and Clark County has 12 rainy days in May with a total of 71.7 mm of rainfall.
UV exposure in Lewis and Clark County during May
Stay informed about UV levels for safe outdoor activities throughout the month of May ☀️
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Where is Lewis and Clark County?Get accurate weather forecasts for Lewis and Clark County, located at latitude 46.593 and longitude -112.036. Stay updated with localized weather information tailored for Lewis and Clark County.
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