Outdoor Events in Chicago in May: Weather and Planning

May is the sweet spot for outdoor events in the Chicago area. The grass is green, the days are long and the heat has not arrived. It is also the wettest month in the 1991-2020 normals, which surprises people who assume summer holds that crown. This guide covers what to expect and what to rent.

May weather by the numbers

At O'Hare, May averages a 70.5°F high and a 50.6°F low, with 4.49 inches of precipitation. Snow is down to a trace. That is the highest precipitation total of any month, a little ahead of August at 4.25 inches and June at 4.10. A pleasant average still includes cool, windy lake-effect days and the occasional storm, so the tent is not optional if the budget depends on the date.

Daylight in May

Sunset is about 7:47 pm on May 1 and about 8:02 pm on May 15 (calculated for 2027). A 5 pm ceremony leaves nearly three hours of good light. By late May you can serve dinner outdoors in daylight. If you plan string lights or uplighting, they still matter for atmosphere after 8:30 pm, and our string light layouts guide shows how far apart to hang them.

Dates that crowd the calendar

Mother's Day is Sunday, May 9, 2027, and Memorial Day is Monday, May 31, 2027. Add graduation parties, first communions and wedding season, and the second half of May books fast. If a weekend matters to you, secure the venue first and the rental list right after. See when to book event chair rentals in Chicago for lead times.

What to rent for a May event

A sample May floor plan

The sketch is one example, not a rule. Tent sizing depends on tables, a dance floor and a bar, and our tent size guide shows the math.

Cool-night comfort

May evenings drop quickly, and the average low of 50.6°F means guests in light dresses and short sleeves will feel it by 9 pm. Planners handle this with heaters under the tent, a basket of wraps or blankets, hot drinks at the bar and tents with at least one sidewall. Lakefront venues are cooler still.

Permits and park rules

In Chicago parks, May is a busy permit season. The Chicago Park District needs a Special Event Permit for outdoor gatherings of 50 or more people and for tents, alcohol, amplified sound or inflatables at any size, and says review takes at least 14 days. Its application for 2027 opens November 6, 2026 at 9 am according to its site. For a suburban park or forest preserve, call that district. Our venue rules guide is a good checklist.

Chairs for May

May is graduation and garden-party season, so lightweight chairs that move easily on grass are useful. The rattan garden chair suits a patio brunch, and the garden folding chair is the budget choice for a large crowd. For a more formal outdoor ceremony, a cross-back chair in natural oak keeps the lawn look clean. Read about ceremony versus reception chairs if you need to move chairs between spaces.

Plan the whole rental list in one call

Book a free 15-minute seating call and we will walk through your date, your venue and your guest count, or request a quote with the details. We help plan chairs, tables, linens, dinnerware, glassware, tents and lighting together, so one conversation covers the whole list. Our first deliveries begin with the 2027 Founding Season in April.