Casper, WY weather in May
In May, Casper sees highs around 67°F and lows around 37°F: mild, with frequent rain. Expect about 11 wet days. Snowfall averages about 2.6 in. Great for outdoor plans.
- Normal high
- 67°F
- Normal low
- 37°F
- Wet days
- 11
- 2.2 in total
- Snowfall
- 2.6 in
- snow on the ground 1 day
How May changes from start to finish
| May 1 | May 31 | |
|---|---|---|
| Normal high | 60°F | 73°F |
| Normal low | 32°F | 42°F |
| Chance of a wet day | 35% | 34% |
| Sunrise / sunset | 5:59 am / 8:05 pm | 5:29 am / 8:36 pm |
| Daylight | 14.1 h | 15.1 h |
Chance of a wet day: average for the first and last 7 days of the month. Times are local clock time (Mountain Time).
A typical May day
- 6 am44°Fdew point 36°F
- 9 am55°Fdew point 37°F
- Noon62°Fdew point 35°F
- 3 pm64°Fdew point 34°F
- 6 pm60°Fdew point 35°F
- 9 pm50°Fdew point 37°F
NOAA hourly normals (local standard time) from Casper Natrona Co Airport (8 mi away); average wind 11 mph; clear or few clouds in 62% of daytime hours, mostly cloudy or overcast in 28%.
What kind of days to expect
- Comfortable dayshigh 65-80°F and dew point under 60°F15 of 31
- Hot dayshigh 90°F or more0 of 31
- Muggy daysdaily mean dew point 65°F or more0 of 31
- Wet daysat least 0.01 in of rain or melted snow11 of 31
- Notable rainat least 0.10 in5 of 31
- Freezing nightslow 32°F or below8 of 31
- Snow on the groundsnow depth 1 in or more1 of 31
Average days per May, counted from daily records for each year 1991-2020.
Rain and snow in May
Normal precipitation is 2.2 in; a dry May brings about 1.0 in and a wet one about 3.0 in (25th and 75th percentiles). About 1 day brings half an inch or more. Normal snowfall is 2.6 in, with about 1 day of an inch or more.
How May varies from year to year
- Warmest May, 1991-20201994: average high 78°F
- Coolest May2019: average high 59°F
- Wettest May1995: 6.3 in
- Driest May2020: 0.3 in
- Highest reading95°F (May 29, 2003)
- Lowest reading17°F (May 2, 2005)
From the station's daily records with NOAA quality flags removed; most recent date shown when a reading repeats.
May compared with April and June
| April | May | June | |
|---|---|---|---|
| Normal high | 56°F | 67°F | 80°F |
| Normal low | 28°F | 37°F | 45°F |
| Wet days | 10 | 11 | 9 |
| Comfortable days | 8 | 15 | 13 |
| Daylight | 13.4 h | 14.7 h | 15.3 h |
Highs change by +11°F from April and +13°F into June.
Nearby alternatives in May
- Warmer: Greeley, CO188 mi · high 75°F · 11 wet days
- Cooler: Keystone, SD162 mi · high 60°F · 13 wet days
How Casper ranks in May
- Normal high317th warmest of 378 cities; 1st of 4 in Wyoming
- Wet days227th driest of 378
- Comfortable days110th most of 339
What to pack for Casper in May
- A warm jacket – lows near 37°F, highs near 67°F
- Layers – afternoons near 67°F but nights near 37°F
- A rain jacket or umbrella – rain or snow on about 11 days
Frost in May
The last spring frost typically comes around May 26; in 1 year in 10 it comes after Jun 10. All frost dates for Casper.
Heating and cooling
May has 409 heating degree days and 4 cooling degree days (base 65°F), 5% of the year's total heating and cooling demand.
Questions
How cold is Casper in May?
The normal high is 67°F and the normal low is 37°F. From 1991 to 2020 the coldest May reading was 17°F (most recently on May 2, 2005).
Does it rain a lot in Casper in May?
About 11 days in May have at least 0.01 in of precipitation, and the normal total is 2.2 in. The wettest May in 1991-2020 was in 1995 (6.3 in); the driest was in 2020 (0.3 in).
Does it snow in Casper in May?
Yes. Normal snowfall in May is 2.6 in, and snow covers the ground on about 1 day.
Is May a good time to visit Casper?
May ranks 1st of 12 months on our comfort score for Casper (74 out of 100). It has about 15 comfortable days. The best month is May.
Where the numbers come from
- Temperature, rain, snowfall, snow depth, frost dates, humidity and wind by hour and cloud cover: Casper Natrona Co Airport (USW00024089), 7.9 mi WNW of the city center, 5,338 ft (233 ft higher than the city). NOAA normals and daily records, 1991-2020.
- Daily humidity and wind: Natrona County International Airport (725690-24089), 8.4 mi WNW of the city center, 5,319 ft (214 ft higher than the city). Hourly observations, 1991-2020.