As warmer weather approaches, many offices are adopting the often-ambiguous dress code of "summer casual," which can leave employees uncertain about how to dress appropriately. While the phrase suggests a relaxed style, experts emphasize that it requires a balance between comfort and professionalism, combining lighter fabrics with a smart, put-together look.

The term "summer" generally implies the use of lighter materials, slightly shorter hems, and the incorporation of more color, though bright or overly loud shades are best avoided. Short-sleeved shirts may be acceptable, provided they are worn under a blazer during most of the day, while shorts remain inappropriate in most office settings, except for some manual outdoor professions. Meanwhile, "casual" does not translate to leisurewear like sweatpants or tracksuits but refers to more relaxed alternatives to typical office attire. Instead of suit trousers, chinos are recommended; polos can replace dress shirts; and driving shoes or loafers serve as substitutes for formal lace-up shoes.

Jeremy Langmead, brand and content director at men’s retailer Mr Porter, describes summer casual as “not so much a dress code as a loosening up,” noting that the wearer should still be clearly office-appropriate but with a fresher and more breathable approach.

A widely accepted formula for this style includes caramel cotton chinos paired with a navy blazer and a white Oxford cotton shirt, or a simple white tee for a more relaxed iteration, complemented by brown boat or driving shoes. Simon Holloway, creative director of the luxury brand Dunhill, identifies this look as an evolution of the “preppy” style popularized in the 1980s, advising investment in authentic, high-quality pieces for lasting appeal.

Fit plays an important role. Chinos ideally should be mid- to high-rise, relatively loose in the legs, and comfortably snug only at the waist. Brands like Uniqlo, Gant, and Ralph Lauren offer popular options covering a range of price points. Blazers should be long enough to cover the backside, accommodating various heights, and are best paired with matching belts and classic loafers, such as those by Tod’s.

For those who experience greater heat sensitivity, selecting breathable fabrics is key. Seersucker’s puckered texture promotes airflow, and tropical wool—characterized by high-twist yarns and open weaves—is increasingly recognized for its suitability in warm weather, offering better wrinkle resistance than cotton or linen. Nicholas Brooke, executive chair at UK brand Sunspel, emphasizes that while wool is commonly associated with winter, certain weaves make it comfortable and stylish in summer. Luxury labels like Saint Laurent offer tropical wool suits with design details such as 1980s-inspired shoulder padding, though more affordable alternatives can be found at brands like Suit Supply.

Seersucker blazers from brands like Gant or more casual yet elegant pieces from Sunspel provide additional warm-weather options.

For those inclined to incorporate more color or patterns into their attire, the recommendation is to follow a “three-colour rule”: one bright or bold piece balanced by two neutral elements. Primary colors tend to pair well with muted tones, creating a stylish but office-appropriate look. Examples include pairing a vermilion shirt with blue jeans and an oatmeal blazer or combining an Indian yellow shirt with white wide-leg denim and a cropped navy military jacket. Langmead suggests ensuring that colors near the face complement one’s complexion and cautions against excessive brightness that could resemble a “gelato counter.”

In summary, summer casual for the office sits between formal business wear and off-duty attire, relying on lighter fabrics, comfortable fits, and tasteful color choices to keep men cool and polished as temperatures rise.