Thornton in Spring

In spring (March, April and May), Thornton sees average daytime highs around 60°F and overnight lows near 34°F, with 7.8 in of precipitation over about 29 wet days across the season. It is the 3rd-warmest season and the wettest season of the year.

Over the season highs climb from about 49°F in early March to 73°F by late May. The sky is clear or mostly clear about 31% of the time across spring, and the air most often feels dry.

Spring is Thornton's 3rd-best season to visit on our travel score. For the whole year in context, see Thornton's year-round climate.

Avg daytime high: 60°F; 3rd-warmest season
Avg overnight low: 34°F
Precipitation: 7.8 in; 29 wet days
Avg wind: 6 mph
Travel score: 4.7; 3rd-best season
Months: Mar · Apr · May

← Winter Thornton year-round climate Summer →

Spring Summer Fall Winter

Temperature in Thornton in Spring

Average highAverage lowShaded bands: 10–90% of days

Over the season highs climb from about 49°F in early March to 73°F by late May.

A typical spring day in Thornton reaches about 60°F and drops to 34°F overnight. The warmest of the three months is May, the coolest March.

How spring really feels in Thornton

Once humidity and wind are folded in, spring brings about 0 days that feel above 90°F and 59 that feel at or below 32°F.

Days feeling ≥ 90°F

heat index over the day's high

Days feeling ≤ 32°F

wind chill below the day's low

The story in spring is cold — wind chill drags the overnight "feels like" below the raw low.

Thornton weather by month

How the three spring months (March, April and May) compare with the rest of the year — the season's months are highlighted.

Month	High / Low (°F)	Rainfall (inches)	Wet days	Snow days	Daylight (hours)	Travel score
Jan	42° / 18°	0.9	5.2	5	9.5	0.3
Feb	44° / 20°	0.9	5.8	5.5	10.4	1.0
Mar	53° / 27°	1.9	7.6	5.7	11.7	3.3
Apr	59° / 33°	2.7	9.9	4.7	13	4.7
May	69° / 43°	3.2	11	1	14.2	6.2
Jun	80° / 52°	2.1	8.3	0	14.8	6.8
Jul	85° / 58°	1.6	7.2	0	14.5	5.5
Aug	83° / 57°	1.5	6.4	0	13.6	6.3
Sep	76° / 49°	1.4	5.8	0.5	12.3	7.7
Oct	64° / 37°	1.6	6.1	2.2	10.9	6.4
Nov	51° / 26°	1.2	6	5.1	9.8	2.9
Dec	42° / 18°	0.8	4.8	4.9	9.2	0.3

Cloud cover in Spring

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 31% of the time across spring.

Chance of precipitation in Spring

Any precipitationSnow

Thornton gets around 7.8 in of rain and snow over 29 wet days across spring. The line is the day-by-day chance of measurable precipitation.

Humidity in Spring

DryComfortableHumidMuggyOppressiveMiserable

Most of spring feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.

Wind in Spring

Winds average 6 mph across spring.

Sunrise & sunset in Spring

DaylightNight

Daylight runs from about 11 hours in early March to 14 h 36 min by late May. The lit band spans sunrise to sunset each day.

Solar energy in Spring

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day across spring, about 6.1 kWh/m².

Planning a trip in spring

Is spring a good time to visit Thornton?

Our two travel scores rate spring for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal), averaged across the three months.

4.7

Sightseeing

3rd-best month of the year

1.3

Beach & pool

3rd-best month of the year

spring is a reasonable time to visit Thornton for sightseeing.

What to pack for Thornton in Spring

From spring's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In spring, Thornton sees daytime highs around 60°F and nights near 34°F. Pack a warm layer and sun protection. Worth having: a heavy coat and rain gear. About 29 days see rain.

a warm layersun protectiona heavy coatrain gear

UV index in Thornton in Spring

LowModerateHighVery highExtreme

Clear-sky midday UV across spring averages around 7 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Thornton peaks around July 12 at about 11 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 23 at about 2 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 10 months of the year.

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
UV index (midday)	2	4	7	6	7	10	11	10	7	5	3	2
Level	Low	Moderate	High	High	Very high	Extreme	Extreme	Very high	Very high	High	Moderate	Low

	UV index (midday)	Level
Jan	2	Low
Feb	4	Moderate
Mar	7	High
Apr	6	High
May	7	Very high
Jun	10	Extreme
Jul	11	Extreme
Aug	10	Very high
Sep	7	Very high
Oct	5	High
Nov	3	Moderate
Dec	2	Low

Air quality in Thornton in Spring

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where spring falls, not just the annual average.

Air quality in Thornton is worst in August — around 21 µg/m³ PM2.5 (moderate), about 1.6× the cleanest month (May, 13 µg/m³).

Modeled monthly averages (CAMS reanalysis, 2015–2024).

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
PM2.5 (µg/m³)	17	15	16	13	13	14	14	21	13	15	15	16
Level	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate

	PM2.5 (µg/m³)	Level
Jan	17	Moderate
Feb	15	Moderate
Mar	16	Moderate
Apr	13	Moderate
May	13	Moderate
Jun	14	Moderate
Jul	14	Moderate
Aug	21	Moderate
Sep	13	Moderate
Oct	15	Moderate
Nov	15	Moderate
Dec	16	Moderate

Location & terrain

Where is Thornton?

Thornton sits at 39.9°N, 105.0°W, 5,351 ft above sea level, in United States. The nearest listed city is Northglenn, 1.2 mi away.

Topography around Thornton

How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of Thornton.

Within 2 miles, the terrain around Thornton has only modest variations in elevation — a maximum elevation change of 472 ft around an average of 5,276 ft above sea level; within 10 miles, significant variations in elevation — a maximum elevation change of 856 ft; within 50 miles, extreme variations in elevation — a maximum elevation change of 9,708 ft.

The land around Thornton is covered by artificial surfaces (68%) within 2 miles, artificial surfaces (45%) and grassland (34%) within 10 miles, and grassland (43%) and trees (30%) within 50 miles.

2 miles

472 ft

artificial surfaces 68%

10 miles

856 ft

artificial surfaces 45%

50 miles

9,708 ft

grassland 43%

treesgrasslandcroplandartificial surfacesbare terrainwatermoss and lichen

← Winter Thornton year-round climate Summer →

Spring weather nearby: Northglenn 1.2 mi · Sherrelwood 2.5 mi · Westminster 4.3 mi · Commerce City 4.3 mi · Broomfield 6.8 mi · Arvada 7.5 mi · Denver 8.7 mi · Wheat Ridge 8.7 mi

United States travel facts

Power plugs: Type A / B; 120 V · 60 Hz
Prices: ≈ 100% of US; price level, 2025
GDP per capita: $90,027; 2025
Happiness: 6.8 / 10; World Happiness, 2025
Safe drinking water: 98%; of population, 2024
Homicide rate: 5.8; per 100k, 2023
Road deaths: 12.7; per 100k/yr, 2019
Income group: High; World Bank
Religion

Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.

Data sources

Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Thornton (39.868°, -104.9719°, elevation 5,351 ft), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google.