WEATHER FORECASTERS are generally obliging when it comes to offering an index of seasonal changes such as pollen in the spring and pollution in the summer. So they ought to consider adding another index of late summer: the smell of grilling sausage and peppers. Next to livestock, there's certainly no other aroma so closely tied to summer fairs.

Judging by our research, the new S/P Index could be pushing 100 percent for the next six weeks.

But there's more to county fairs than what's on the grills -- like what's on the hoof -- cows, sheep, pigs, chickens and dogs.

Part of the fun is watching the other fairgoers. Weeeooooo! So are the demolition derbys and the new craze, mud bogs -- guys deliberately steering their four-wheel-drive vehicles into four feet of thick mud, all for applause and a ribbon. Then there's the greased pig scrambles, the greased pole competitions, the pet parades and the baby beauty contests.

And don't forget about the music because there's always plenty of it. This year you'll find the O'Kanes, the Johnson Mountain Boys and the Nichols Brothers each playing at several places, Loretta Lynn and Tammy Wynette at the Great Frederick Fair, Bill Haley's Comets at the Calvert County Fair, the Four Tops at the Virginia State Fair in Richmond, and the Hubcaps will be back at the Montgomery and Prince George's fairs.

Some of fairs reflect the county's history. The St. Mary's County Fair in Maryland's southern-most county each year holds a Queen of Tolerance contest. The name is a reminder that the state was founded on religious tolerance 350 years ago when the Ark and the Dove landed on the shores of the St. Mary's River, less than 10 miles from the current fairgrounds.

In neighboring Charles County, farmers may be growing less tobacco today but the fair's board members remember the region's roots each year with the Queen Nicotina contest.

"There have been several efforts to change the name because of the anti-smoking lobby," says board member Joe Gardiner, "but you won't get that past the fair board for love or money. It's just simply a tradition."

The Charles County Fair, now in its 64th year, began as a tobacco fair and festival and last year attracted more than 50,000 guests. During the fair days, you can can visit the Farm Museum displays of dozens of rare tools dating back to the turn of the century.

Speaking of big crowds, Joe Johnson, manager of the 38th annual Prince William County Fair which begins this Friday, hopes to beat last year's whopping crowd of 102,000. The fair charges an admission of $7 per person which includes endless midway rides (including the huge, 110-foot ferris wheel), demolition derbys, stunt car acts and top-notch musical acts.

"You look at what you get and it's a real bargain," says Johnson. "It's good for the families."

Here's a roundup of fairs in the area: MARYLAND

FRIDAY & SATURDAY:

31st annual Garrett County Agricultural Fair, McHenry. From I-270 north (turns into U.S. 70 west) take U.S. 40 west to Cumberland (turns into U.S. 48 west), then Maryland Route 219 (exit 14) south and follow signs to the fairgrounds. Admission $4, includes parking, demolition derby, rides and race track shows.

Fair is open from 8 to 10; exhibit building Friday from 10 to 10, Saturday from 10 to 8:30. Special attractions beginning Friday: computer program at 10 with computer fair at 1, lawn and garden tractor pull at 2, washed lamb contest and horse pull at 7, the Keystone band performs at 7 and 9. Saturday: dog contest at 11, horse show at noon, wood cutting contest at 1, pedal tractor pull at 7 and 9, livestock sale at 7:30, championship horseshoe pitching at 8. 301/334-1948.

AUGUST 21-29:

Montgomery County Fair, Montgomery County Fairgrounds, Gaithersburg. From I-270 north take Route 124/Montgomery Village Avenue east to Route 355, turn south and drive to the fairgrounds. Fair is open 7 to midnight. Carnival begins at 4 opening day; at noon August 22; at 1 August 23; all other days at 9:30. Admission: adults, $3; kids 12 to 15, $2; under 12 free. Parking: $2.

Free admission and free parking on August 21 & 22; $1 admission on August 23. Bring a Pepsi product those days and ride for $8 all day. Special attractions include daily duck and pig racing; Vic Hyde, the one-man band; High Pockets Stilt walkers through Thursday. Sunday is 4-H day and features a horse show at 8, natural colored sheep show at 11, parade and queen contest at 7, cake at auction at 8:30, 4-H dance at 10. Monday: free admission to school-age kids, 7 to 6. Tuesday: free admission to seniors (60 years and older) from 7 to 6; dairy goat, cattle and swine judgings at 9, tractor operating contest at 10, draft horse show at noon, horse pull at 7. Wednesday: pretty cow contest at noon, pretty goat contest at 5, tractor pull at 6:30. Thursday: 4-H beef breeding at 9, sheep judging at 10, 4-H dairy cattle fitting and showing at 2, demolition derby at 8, selection of supreme dairy animal at 10. Friday: open class sheep judging at 10, invitational dairy goat judging contest at 4, $200,000 livestock auction at 6:30, Stoney Roberts demolition derby at 8. Saturday, August 29: regular 4-wheel street machines compete in four-foot deep mud bog at 4.

Featured musical acts are Friday: Highway 101 at 7 and 9. Saturday: Judy Rodman at 7 and 9. Sunday: Johnny Glaze Band at 2 and 4. Monday: The Hubcaps at 7 and 9; Nichols Brothers at 7 and 10. Tuesday: The Sweet Adelines at 8:30; Jimmy Purdum Band at 7 and 9. Wednesday: Gary's Angels at 7; Lighthouse Trio at 9. Thursday: Lighthouse Trio at 5; Johnny Glaze Trio at 7 and 9. Friday: Lighthouse Trio at 8. Saturday: U.S. Navy's Electric Brigade at 6; Johnson Mountain Boys at 8 and 10. 926-3100.

AUGUST 29 TO SEPTEMBER 7:

Maryland State Fair, Timonium. Off I-83 north, exit 17. Fair open daily 10 to 10; midway open noon to 11:30. Daily admission including thoroughbred race track: adults $3; kids ages 11 and under free.

Horse racing with parimutuel betting from 1 to 6:30 daily. Newest additions to fair are a food pavilion featuring Maryland-produced beef, pork, eggs, vegetables and seafood, and viewer's choice in the needlepoint and weaving competition. Special events are Monday: English horse and pony show at 8:30 a.m., beef show at 8:30 a.m.; dairy goat show at 9 a.m., dairy cow contest in the Holstein Futurity Pageant September 6 at 8 p.m.

Featured musical acts on Saturday: The Sundance Express at 7; Peebles and The Bam-Bam Boys at 8. Sunday: Baltimore Country at 7; Bobby and the Believers at 7. Monday: Bite the Bullet at 7; Word of Mouth at 8. Tuesday: Stardells at 7; Great Train Robbery at 9. Wednesday: New Early Sunrise Band at 7; Heat and the Cold Sweat Horns at 8. Thursday: Cry Monday at 9. Friday: The Georgia Overdrive at 7; Wind at 8. Saturday: Smile at 8. Sunday: Group Therapy at 8. Monday, September 7: The Cha-Cha Boys at 8. 301/252-0200.

SEPTEMBER 9-13:

Prince George's County Fair, county equestrian center, U.S. 301 and Maryland Route 4, Upper Marlboro. Open Wednesday and Thursday, 4 to 10; Friday though Sunday 11 to 11. Admission: adults $4, ages 7 to 12, $2; 55 and older, $3; 6 and under free.

The state's oldest fair dates to 1842. Thousands of agricultural and arts-related exhibits, tethered hot air balloon rides, daily pig races and scarecrow-making.

The tobacco spitting contest has dribbled away, making room this year for the September 12 Atlantic Coast Arm Wrestling Championship at 1 and hay bale tossing contest at 3. Also new this year are the daily trout fishing competitions. Special attractions begin Wednesday with beautiful baby contest at 5, Miss Prince George's County Fair contest at 7. Thursday: the Hubcaps at 7:30 and 9:30; laser light show at 9. Friday: horse pull at 7, the Hubcaps at 8 and 10. Saturday: day-long livestock judging begins at 8:30 a.m.; clog dancing from 11 to 5; hot air balloon rides, 4 to 7; bluegrass by Grazz Matazz at 8 and 10; Ritchie Reunion at 9. Sunday: "International Day" noon to 9 features music by a West African band, Irish and German folk music groups, Chinese dragon dancers, Ecuadorian dancers, the Prince George's County Police Drum and Bagpipe Band and the Seldom Scene. After August 30, 952-0270).

SEPTEMBER 16-20:

Anne Arundel County Fair, Crownsville. Take U.S. 50 east to Parole/Crownsville exit. West on Route 178 to Crownsville for four miles, follow signs to fairgrounds. Admission: adults $3; ages 6 to 10, $1, under 6 free. Open Wednesday and Friday 4 to 11; Thursday 1 to 11; Saturday 8 to 11; Sunday 8 to 9.

Special attractions begin on Wednesday: light draft horse pull at 7, queen contest and band performance at 8. Thursday: senior citizen's talent show at 1:30, Pascal Go Getters at 2:30, heavy draft horse pull at 7, the Third Degree band at 7 and Grand Theft band at 9. Friday: swine show at 5:30, dairy cattle show at 6:30, police vs. firemen tug-o-war at 7:30, and Can Do band at 8. Saturday: horseshoe pitching and baby show at 9, bicycle rodeo at 1, square dancing at 1, auto driving contest at 2, Bay Winds band at 2, pie-eating contest at 3, hog-calling contest at 3:30, WCA0-AM/Nashville Network talent search at 5:30, tractor and truck pull at 6:30 and the Stardells at 8. Sunday: Smiley the Clown all day, antique car show at 10, watermelon-eating contest at 2, square dancing at 2:30, dog show at 3, kids' pet parade at 4, the Stardells and the O'Kanes that afternoon. Call 301/923-3400 or 301/255-5632.

SEPTEMBER 17-20:

Charles County Fair. Take Maryland Route 5 south to U.S. 301 south to fairgrounds two miles south of LaPlata. Open Thursday 5 to 11:30, daily thereafter 9 to 11:30. Admission: adults $2 (four-day pass $4); 11 and under, free. Friday is kids' day (anyone up to age 18 gets in free 9 to 5).

Special attractions begin Thursday: The Queen Nicotina contest at 7. Friday: talent show at 7. Saturday: baby show with eight classes at 10, light draft horse pull at 7, and Crakken performs at teen dance at 7:30. Sunday: Feedback band at noon, heavy draft horse pull at 2, Southern Merry-landers Square Dancers at 2:15. Call 301/843-9314 (or 301/932-1234 during fair week).

SEPTEMBER 18-20:

Baltimore City Fair, Baltimore Fairgrounds, under the Jones Falls Expressway between Saratoga and Madison streets, Baltimore. Hours: Friday and Sunday noon to 10; Saturday 10 to 10. Admission: $3, includes unlimited midway rides. Featured entertainers are: Crowded House Friday and The Temptations Sunday.. 301/547-0015.

SEPTEMBER 21-26:

Great Frederick Fair, East Patrick Street, Frederick. Take the first Frederick exit on I-270 and follow signs to fairgrounds. Hours: 10 to 10. All musical performances at 6:30 and 9 p.m. Admission $2; children under 10 free.

Midway, livestock shows and sales, agriculture and farm equipment exhibits, arts and crafts shows, games and tractor pulls (Monday and Tuesday, 6:30 p.m.) and demolition derby (Wednesday 7:30). Reserved seating $8; general admission $6.

Entertainment includes Loretta Lynn (Thursday), Charlie Pride & Ray Price (Friday) and Randy Travis and Tammy Wynette (Saturday). Reserved seats $12; general admission $6. For Hell Drivers Saturday at 1, reserved seats are $7, general admission $5. 301/663-5895.

SEPTEMBER 24-27:

St. Mary's County Fair, Leonardtown. Take Maryland Route 5 to the county fairgrounds two miles south of Leonardtown. Open Thursday from 3 until 9, Friday though Saturday 9 to 9; Sunday: 9 to 6. Admission: $3; 6 to 12, $1; under 6 free.

Special attractions begin on Thursday with the Queen of Tolerance contest. Friday: (kids and students are admitted free) a horse show, speech contest, clown show, rock bands and a light draft horse pull. Saturday: floats, marching bands, pet show, square dancing, jousting tournament, bluegrass music, heavy draft horse pull and 4-H livestock auction at 4. Sunday: baby show, horse show, gospel music show, $5 carnival ride pass. Demonstrations in wool spinning and lacemaking daily. Call 301/475-2707 or 301/475-8434.

SEPTEMBER 30 THROUGH OCTOBER 4:

Calvert County Fair, Prince Frederick. From Maryland Route 4 to Prince Frederick, turn left on Dares Beach Road and drive a quarter mile to the fairgrounds. Open Wednesday and Thursday 4 to 11:30, Friday and Saturday 9 to midnight, Sunday 9 to 6. Admission: $2, 12 and under free. Sunday admission: $7, 12 and under free. Special attractions at Calvert's 101st fair begin Wednesday with a cake auction at 7, teen dance at 8. Thursday: dog show at 5, pie eating contest at 6 and high schools' barber shop quartet singing at 8. Friday: petting zoo at 10, light and heavy weight horse pull at 6, "Guys and Dolls" at 7 and the Bruce Van Dyke Band at 9. Saturday: parade at 10, Calvert School of Dance at 11:30, baby contest at 12:30 and 3:30, variety players at 2:30, sheep auction at 4, car show at 5:30, Diane Herbert Dancers at 6:15, Top 40 disc jockey spins tunes for dancing at 8. Sunday: pretty animal contest at 1, Bill Haley's Comets at 2 and 4, Tri-County barber shop singing at 3. Call 301/586-0523 (or 301/257-2308 and 301/535-0026 during fair week). VIRGINIA

FRIDAY THROUGH AUGUST 22:

Prince William County Fair, Prince William County Fairgrounds, Manassas. From I-66, take Route 234 south seven miles. Gates open noon to midnight; midway open at 2. Daily admission includes parking, all grandstand shows, circus performances and unlimited midway rides: visitors ages 3 to 59, $7; 60 and older $3; under 3 free.

Special events include the return of the Robinson Family Country Music Show, which performs daily except August 22, the Herriott Family Trained Animal Circus with two shows weekdays and three otherwise, the Hollywood Stunt World on opening night at 8, and mud bog for cash prizes on August 22 at 6.

Also scheduled are Friday: baby contest (ages 9 to 18 months) at 1 and the Miss Prince William County Fair Pageant at 8. Saturday: children's pet show at 2, U.S. Tae Kwon Do Center demonstration at 4, tractor and truck pull at 5 and Star Twirlers square dance exhibition at 8. Sunday: poultry judging at 1, children's pet show at 3 and tractor and truck pull at 4. Monday: beef cattle and rabbit judging at 1, dairy showing judging and fitness classes at 7:30 and Chicago Knockers mud wrestling at 8. Tuesday: dairy cattle judging at 1, The Country Gentlemen, Johnson Mountain Boys, Down Home Bluegrass and Chandler and Fairfax at 7 and 9. Wednesday: dairy goat judging at 9, sheep judging at 1, parade of champions at 7 and professional wrestling at 8. Thursday: swine judging at 1 and demolition derby at 8. Friday: baby contest at 1, pony judging at 1, country music from Ricky Van Shelton and the O'Kanes at 7 and 9, Manassas martial arts demonstration at 7 and Northern Virginia District dairy show calf dressing contest at 8. Saturday: 4-H open horse show at 9, the district dairy show, showing and fitting classes at 10, district dairy show, type classes, mud bog at 6 and Rawhide and Ruffles square dance exhibition at 7:30. 703/368-0173.

FRIDAY AND SATURDAY:

Greater Shenandoah Valley Fair, Eastside Speedway, Waynesboro. Take U.S. 29 south to Charlottsville, take I-64 west then U.S. 340 north to the speedway. Open daily 5 to 1. Admission per carload: $3.50. Grandstand show prices $8.

Exhibits include crops and vegetables, honey, baked and canned goods, clothing, crafts, rugs, foil art, ceramics, photographs, and a hint of Christmas in August.

With mountains on three sides, this fair is deep in the heart of Virginia farm country. Special attractions include three diving mules performing three times daily. Friday: Tanya Tucker and Whiskey Creek at 7 and 9. Saturday: greased pole climbing all day, baby beauty pageant at 3 and stock car racing at 7. Call 703/943-9336.

AUGUST 20-23:

Arlington County Fair, Thomas Jefferson Community Center, 3501 S. Second Street, Arlington. Take the free shuttle from Metro's Orange line Virginia Square stop or the Career Center parking lot at 816 S. Walter Reed Dr. Friday through Sunday. Open Thursday 8 to 10, Friday and Saturday 10 to 9, Sunday noon to 5. Free.

Special attractions include petting zoo (except Thursday), pony rides, ferris wheel, moon bounce, baseball dunking tank, rollerskating, vollyball, ping pong, dancers, unicycle troupe, musical performances (inside stage), ethnic foods and fire department helicopter rescue demonstrations. On Saturday there'll be a Republicans vs. Democrats softball game at 4 p.m. Exhibits include entries in crafts, photography, fine arts, dolls, vegetables and foods. Call 553-8522 or 558-2475.

AUGUST 23-29:

Page Valley Agricultural and Industrial Fair, Luray. Take I-66 west to U.S. 340 south, then an immediate left on Collins Avenue and follow signs to fairgrounds.

Open Sunday 1 to 11, Monday through Friday 5 to midnight, Saturday noon to midnight. Daily admission includes parking and grandstand performances: adults $2.50; 12 and under $1.50. Season tickets: adults $10; children $4. Kids' Day (Tuesday) features unlimited midway rides for $5.

Sunday: a horse show at 1, baby contest at 5:30, beauty contest at 7:30. Monday: a beef heifer show at 6, steer show at 7 and Nashville stars The Kendalls at 7 and 9. Tuesday is 4-H kids' day: a kids' Olympics at 10, dairy show at 12:30, goat show at 1:30, horse show at 3, hog show at 6, lamb show at 7 and animal dressing show at 8. Wednesday: 4-wheel drive truck and open tractor pull at 7. Thursday: fashion show at 5:30, performing arts show at 6:30, steer, lamb and hog auction at 8 and the Nichols Brothers band at 7 and 9. Friday: 4-H tractor driving contest at 10, bicycle rodeo at 10, junior stockman contest at 1, pet show at 3 and demolition derby at 7. Saturday: garden tractor pull at 2, Whiskey Creek Band at 7 and 9. Call 703/743-3070 (703/743-5240 during fair week).

AUGUST 24-29:

Clarke County Fair, Berryville. From I-66 west take Route 340 north then Route 7 west for a mile to fairgrounds.

Open Monday 5 until 11, Tuesday through Saturday 8:30 to around midnight; midway open at 6. Admission: $3; 6 to 15 $1; under 6 free.

Special attractions for Clarke County's 33rd annual fair begin on Monday: all carnival rides $6 after 5, Clarke County High School Band at 7:10, Clarke County Twirlettes Baton and Drum Corps at 7:30, Miss Clarke County Fair contest at 8. Tuesday: livestock judging begins at 1, pet show at 5:30, dairy show at 6, building exhibits (except floral) open for the first time after judging at 6, Little Miss Clarke County Fair contest at 7:30. Wednesday: kids' day (those under 15 admitted free until 5), sheep show at 8:30, poultry show at 9, beef cattle show at 1:30, reduced prices for carnival rides from 2 to 5, beef and chicken barbecue at 5, fancy show horses at 7, Free Wheelers Driving Group and Earl McDonald at 7:30, Kathy Mattea band at 8:30. Thursday: senior citizen day (65 and older admitted free until 5), swine show and horse and pony show at 9, barbecue at 5, livestock champions parade at 7, horse pulling contest at 8. Friday: horse and pony show at 8:30, barbecue at 5, calf scramble at 8:45, Back Country band at 9. Saturday: horse show at 9, barbecue at 4:30, tractor pull at 6, kids' and ladies' greased pig scrambles at 8, Nichols Brothers band at 9:30 and fireworks at midnight.

SEPTEMBER 24 THROUGH OCTOBER 4:

State Fair of Virginia, Richmond. Take I-95 south to exit 17 and follow signs to state fairgrounds. Fair is open daily 8 to midnight; exhibit buildings open 10 to 10, Sundays 11 to 9; midway open Monday, Thursday, Friday at 1, rest of week at noon. Admission includes all events and midway rides: adults $8.95; seniors $6.95: $3 special on September 28. Advance ticket sales for $6.95 available at Crown gasoline stations in Northern Virginia, Richmond and Virginia Beach area, and some AAA dealers.

Bob Eubanks returns this year to host the "Newlywed Game" on Monday, September 28 at 3 and 8 p.m. Other attractions include Young MacDonald's Farm with a range of mini-livestock, from suckling pigs to baby ducks on a water slide, and more than 5,000 head of livestock on display. There's also daily lumberjack shows, a circus show, an ice show, a parade daily at 6:30 and pig racing all day long. Woooeeee! There'll also be stunt car exhibitions on certain days.

Special attractions begin with singer Helen Cornelius on September 28 at 7; Jerry Clower, September 29 at T. Graham Brown, September 30 at 8; The Four Tops, October 1 at 8; Ronnie Prophet, October 3 at 8. Call 804/228-3200. WEST VIRGINIA

AUGUST 21 to 29:

West Virginia State Fair, Fairlea. Take I-66 west to I-81 south to I-64 to the Lewisburg exit. Take West Virginia Route 219 south two miles to Fairlea. Hours 8 to midnight. Admission $3.50, under 13 free. August 21: $7 admission includes all rides and grandstand shows featuring Steve Wariner. Concert prices other days $5 to $13.

Harness racing, horse shows, champion livestock auction, draft horse pulling contest, 4-H demonstrations, midway, West Virginia crafts. Free circus.

Performances Saturday: Ray Stevens and Lee Greenwood and the Jets. Sunday: Charley Pride. Monday: George Strait. Tuesday: Ricky Scaggs. Wednesday: Sawyer Brown and Eddie Rabbitt. Thursday: Randy Travis. Friday: The Judds. Saturday: The Statler Brothers. 304/645-1090.