During my time taking classes as part of Penn State University’s Undergraduate Certificate in Weather Forecasting, we were taught that understanding the climatology of the location you are interested in is an important prerequisite for making accurate forecasts. This post continues on this theme, adding a climatology for April.

Other Month’s Climatologies

January
February
March
May
June
July
August
September
October
November
December

Station Basic Information

City Name / Station ID: New York, NY (LaGuardia Airport – KLGA)

Local Geography and Topography

Station Elevation: 10 feet above sea level.

Station Location: LaGuardia Airport (KLGA) is situated on the north shore of Queens along the East River, approximately 6 miles east-northeast of Midtown Manhattan.

Important Topographical Features: New York City is located in the extreme southeastern corner of New York State, bordering suburban New Jersey and Connecticut. These suburban regions combined with those in Long Island comprise the Greater New York City Metropolitan Area, which is the most populous urban agglomeration in the United States and one of the populous urbanized areas in the world with an estimated population of 18 million. New York City itself sprawls across the coastal plain around the Hudson River estuary. The terminal moraine formed by glaciers of the last Ice Age result in a ridge of higher terrain that cuts a swath from southwest to northeast across the boroughs from northern Staten Island, northern Brooklyn, southwestern through central and northeastern Queens. Otherwise, the city itself is low lying. This ridge varies in height between 200-400 feet, rising sharply from south to north, but tapering more gently north. North and west of the city (about 30-50 miles away), lie significant elevations of the Catskills (north), Poconos (west), Taconics that are part of the broader Appalachian Mountain Range. The elevations of the lower foothills can range from 1000-1500 feet. Some of the elevations in the Poconos and Catskills, west and north of KLGA respectively, peak between 2000-3000 feet. The open expanse of the Atlantic Ocean lies south of KLGA and New York City. Long Island Sound also lies east-northeast. The vast urbanized area of the NYC metropolitan region has significant effects on local microclimates via differential heating (urban heat island effect). KLGA is in a low-lying area sensitive to UHI effects and marine influences.

Per the Local Climatological Data report from the National Weather Service:

On winter mornings, ocean temperatures which are warm relative to the land reinforce the effect of the city heat island and low temperatures are often 10-20 degrees lower in the inland suburbs than in the central city. The relatively warm water temperatures also delay the advent of winter snows. Conversely, the lag in warming of water temperatures keeps spring temperatures relatively cool. One year-round measure of the ocean influence is the small average daily variation in temperature.

National Weather Service – NYC Office

Wind Patterns

Below is a wind rose – you can read more about how to interpret this chart here.

Frequency (percentage) of the single most common wind direction: Due northwest occuring about 13% of the time.

Directions that are most and least common: Most common wind directions following due northwest are due south (10%), west-northwest (9%), and due northeast (8.75%). Least common wind directions are east-southeast (1.25%), due east (2.5%), and due southeast (2.75%).

Direction(s) most likely to produce the fastest winds: Winds from the northwest, west-northwest, and to some extent the northeast and east-northeast tend to produce the fastest winds.

Direction(s) least likely to produce the fastest winds: Winds from the east-southeast, due east, and south-southwest are least likely to produce the fastest winds.

Impacts of wind direction on local weather: Like March northwesterly winds during April are likely tied to the passage of cold fronts and coastal storms. Cold air advection from these winds will still be quite robust during the beginning of the month especially, as record lows for this month suggest. Winds from the northeast are still tied to backdoor cold fronts arriving from the Canadian Maritimes, bringing a moist, cool maritime polar air mass, or the advance of coastal Nor’easter type storms. During April, sea surface temperatures around NYC become markedly cooler than the air temperature as average highs continue climbing in response to more direct sun angle on longer spring days. On days approaching record warmth, in an overall environment of otherwise light winds, you could even see some sea breezes start forming along the coasts.

Maximum observed two-minute wind speed for the month: 48 knots (55 mph).

Temperature and Precipitation Averages/Records

Temperature units are in Fahrenheit and precipitation is in inches.

Worth Noting

April is the first month in the spring when record high temperatures exceed 90ºF. Record lows still routinely dip into the 20s during this month, reflecting the variability that spring can bring. The most recent record low was set in 2021, at 29ºF for 4/2. April also has the second highest single day precipitation record with 6.69″ falling on 4/15.

Date	Normal High	Normal Low	Record High	Record Low	Record Lowest Max	Record Highest Min	Normal Precip	Record Precip
1	55	40	80	27	42	56	0.14	1.89
2	56	40	79	29	39	55	0.14	1.66
3	56	40	77	25	39	53	0.14	1.59
4	57	41	76	24	36	56	0.14	1.74
5	57	41	74	25	38	53	0.14	2.12
6	57	41	80	22	40	53	0.14	2.45
7	58	42	91	22	30	63	0.13	2.00
8	58	42	89	25	38	67	0.14	2.03
9	59	42	84	26	40	64	0.15	2.28
10	59	43	82	29	39	53	0.14	2.85
11	59	43	82	32	42	57	0.15	0.94
12	60	43	86	29	44	54	0.14	1.72
13	60	44	85	25	36	59	0.14	1.63
14	60	44	84	27	41	58	0.14	0.93
15	61	44	86	28	40	64	0.14	6.69
16	61	45	89	31	44	68	0.13	2.50
17	62	45	94	32	45	73	0.13	1.71
18	62	45	91	35	45	69	0.12	0.58
19	62	46	85	35	40	70	0.13	1.41
20	63	46	85	35	47	63	0.13	1.89
21	63	46	86	33	40	61	0.13	1.84
22	63	47	85	33	44	61	0.13	1.90
23	64	47	85	36	44	57	0.12	2.21
24	64	47	87	36	46	59	0.13	2.06
25	64	48	88	36	48	59	0.12	1.50
26	65	48	91	37	47	63	0.13	1.33
27	65	48	89	38	45	61	0.13	1.85
28	66	49	89	36	41	68	0.12	2.64
29	66	49	88	36	49	65	0.13	1.00
30	66	49	89	42	47	60	0.11	5.26
Range	55-66	40-49	74-94	22-42	30-49	53-73	0.11-0.15	0.58-6.69