Thornton, CO weather in May
Thornton is mild in May, with frequent rain: highs average 72°F and nights drop to about 43°F. Expect about 10 wet days. Snowfall averages about 1.4 in. A great month for outdoor plans.
- Normal high
- 72°F
- Normal low
- 43°F
- Wet days
- 10
- 2.4 in total
- Snowfall
- 1.4 in
- normal snowfall
How May changes from start to finish
| May 1 | May 31 | |
|---|---|---|
| Normal high | 66°F | 78°F |
| Normal low | 38°F | 49°F |
| Chance of a wet day | 30% | 30% |
| Sunrise / sunset | 6:00 am / 7:53 pm | 5:33 am / 8:21 pm |
| Daylight | 13.9 h | 14.8 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 am48°Fdew point 38°F
- 9 am59°Fdew point 37°F
- Noon66°Fdew point 35°F
- 3 pm67°Fdew point 35°F
- 6 pm63°Fdew point 37°F
- 9 pm54°Fdew point 39°F
NOAA hourly normals (local standard time) from Aurora Buckley Fld ANGB (16 mi away); average wind 9 mph; clear or few clouds in 29% of daytime hours, mostly cloudy or overcast in 54%.
What kind of days to expect
- Comfortable dayshigh 65-80°F and dew point under 60°F15 of 31
- Hot dayshigh 90°F or more1 of 31
- Muggy daysdaily mean dew point 65°F or more0 of 31
- Wet daysat least 0.01 in of rain or melted snow10 of 31
- Notable rainat least 0.10 in6 of 31
- Freezing nightslow 32°F or below2 of 31
- Snow on the groundsnow depth 1 in or more0 of 31
Average days per May, counted from daily records for each year 1991-2020.
Rain and snow in May
Normal precipitation is 2.4 in; a dry May brings about 1.3 in and a wet one about 2.8 in (25th and 75th percentiles). About 2 days bring half an inch or more. Normal snowfall is 1.4 in.
How May varies from year to year
- Warmest May, 1991-20201994: average high 77°F
- Coolest May1995: average high 60°F
- Wettest May2015: 6.5 in
- Driest May2006: 0.4 in
- Highest reading96°F (May 30, 2003)
- Lowest reading25°F (May 1, 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 | 63°F | 72°F | 84°F |
| Normal low | 34°F | 43°F | 53°F |
| Wet days | 8 | 10 | 7 |
| Comfortable days | 13 | 15 | 10 |
| Daylight | 13.3 h | 14.4 h | 14.9 h |
Highs change by +9°F from April and +12°F into June.
Nearby alternatives in May
- Warmer: Pueblo, CO113 mi · high 77°F · 8 wet days
- Drier: Taos, NM241 mi · high 70°F · 5 wet days
- Cooler: Estes Park, CO46 mi · high 60°F · 12 wet days
How Thornton ranks in May
- Normal high239th warmest of 378 cities; 4th of 17 in Colorado
- Wet days195th driest of 378
- Comfortable days100th most of 339
What to pack for Thornton in May
- Layers – afternoons near 72°F but nights near 43°F
- A rain jacket or umbrella – rain or snow on about 10 days
Frost in May
The last spring frost typically comes around May 2; in 1 year in 10 it comes after May 14. All frost dates for Thornton.
Heating and cooling
May has 257 heating degree days and 26 cooling degree days (base 65°F), 4% of the year's total heating and cooling demand.
Questions
How hot is Thornton in May?
The normal high is 72°F and the normal low is 43°F. From 1991 to 2020 the hottest May reading was 96°F (May 30, 2003).
Does it rain a lot in Thornton in May?
About 10 days in May have at least 0.01 in of precipitation, and the normal total is 2.4 in. The wettest May in 1991-2020 was in 2015 (6.5 in); the driest was in 2006 (0.4 in).
Does it snow in Thornton in May?
Yes. Normal snowfall in May is 1.4 in.
Is May a good time to visit Thornton?
May ranks 1st of 12 months on our comfort score for Thornton (72 out of 100). It has about 15 comfortable days and about 1 day at 90°F or hotter. The best month is May.
Where the numbers come from
- Temperature, snowfall and snow depth: Denver-Stapleton (USW00023062), 9.1 mi SE of the city center, 5,286 ft (61 ft lower than the city). NOAA normals and daily records, 1991-2020.
- Rain and frost dates: Northglenn (USC00055984), 3.1 mi NW of the city center, 5,407 ft (60 ft higher than the city). NOAA normals and daily records, 1991-2020.
- Humidity and wind by hour and cloud cover: Aurora Buckley Fld ANGB (USW00023036), 16 mi SE of the city center, 5,663 ft (316 ft higher than the city). NOAA normals and daily records, 1991-2020.
- Daily humidity and wind: Denver International Airport (725650-03017), 17 mi E of the city center, 5,404 ft (57 ft higher than the city). Hourly observations, 1991-2020.