Molly Weasley

Molly is a very kind person, and gladly took on Harry as a sort of adopted son when she learned of his home situation (OP5). When angry, though, she can be rather overbearing and tends to explode (CS3, OP24). This almost certainly stems from her protectiveness; she lost her brothers Fabian and Gideon to Death Eaters in the first war, and her greatest fear is the death of one of her own (OP9). Molly is short and plump, with red hair (PA1) and a kind face (CS3). She was sorted into Gryffindor. She was part of the 1990s Order of the Phoenix.
Molly met Arthur (who in private calls her “Mollywobbles”) at Hogwarts, eloping shortly after graduation (HBP5, HBP6). She soon began having children, who she home-schooled (WBD), along with doing the cooking and cleaning, while her husband worked at the Ministry (CS3). Though she always wanted a daughter (DH19) and seems most protective over Ginny (DH36), Molly is always keeping an eye on her whole family, thanks in part to her magical clock which informs her of their locations (GF10). Her children have always done their part in keeping her hands full, too – particularly the twins, who seem exceptionally good at earning her wrath (GF5), and Percy, who disowned the family for two years (OP4).

When Ron became friends with Harry Potter, Molly became a mother figure for him as well; she fears his death quite as much as those of her own children (OP9) and treated Hermione rather coolly for a while when Witch Weekly reported her treating Harry poorly (GF28). She and Bill also come to Hogwarts in place of his family during the Triwizard Tournament (GF31).

Molly seems rather short of temper and even ornery at times while she was staying at the headquarters of the Order, but this attitude is somewhat explained by her reaction to the Boggart who had taken up residence in a drawing room desk. When confronted, her worst fears became apparent as the Boggart changed shape to show her all her family one by one, lifeless, killed in the war with Voldemort (OP9). Molly Weasley carried these worries and fears with her as the war against Voldemort and his Death Eaters came to a ferocious close.

In the Battle of Hogwarts, Molly fought along with the rest of her family, which was forever changed when Fred was killed by a collapsing wall. Later, when Bellatrix attacked Ginny, Molly mounted a fierce counterattack and single-handedly did something that had been attempted unsuccessfully by many powerful wizards before her: dueled with and finished off the murderous Bellatrix Lestrange, and revenged the Longbottoms, Sirius, Dobby and Tonks (DH36).

Family

FAMILY & FRIENDS
Ancestry: Pure-blood.
Parents: Molly and Sirius are "cousins by marriage," (OP6) so her parents are probably related in some way to the Prewetts on the Black Family Tree (see BFT and Weasley notes).
Location of childhood home:?
Siblings: Gideon and Fabian Prewett who were violently killed during Voldemort’s first reign of terror. According to Moody, they died like heroes (OP9). It may or may not be a coincidence that Fred and George share the same initials as Fabian and Gideon. Ron's uncle Bilius (PA6) may also be a sibling of Molly's.
Aunts & uncles: "Our Great Auntie" Muriel whose tiara she offers to Fleur (HBP14, 29) (see also Weasley family notes).
Cousin: Unnamed Muggle accountant whom the Weasleys never speak of (PS6). In early drafts of Harry Potter and the Goblet of Fire this cousin had a daughter named Mafalda, but she was eventually edited out of the story (JKR).
Spouse: Arthur Weasley; it appears that Molly and Arthur eloped c. 1968 as the first wizarding war was heating up (HBP5).
Children: Bill (1971), Charlie (1973), Percy Ignatius (1976), Fred (1978), George (1978), Ronald Bilius (1980), and Ginevra Molly (1981).
Grandchildren: at least twelve, known: Dominique Weasley, Victoire Weasley, Louis Weasley, Molly II Weasley, Lucy Weasley, Fred II Weasley, Roxanne Weasley, James Sirius Potter, Albus Severus Potter, Lily Luna Potter, Hugo Weasley, and Rose Weasley.(DH/e, YL).
Home as an adult: “The Burrow,” Ottery St. Catchpole, Devon, near the Portkey at Stoatshead Hill. Other families in the area: the Diggorys, the Fawcetts, and the Lovegoods. The Burrow became the headquarters for the Order of the Phoenix in 1997.
Pet: Errol, the family owl.

Skills

Cooking, knitting, loving her family, healing minor injuries.

Other canon notes and references

We have seen her wearing “a flowered apron with a wand sticking out of the pocket” (CS3).“ long robes in varying states of shabbiness” (GF4), an old green dressing gown (HBP5).  A "midnight blue witch's hat glittering with what looked like tiny starlike diamonds, and a spectacular golden necklace" (HBP16).

Books that Molly owns: Charm Your Own Cheese, Enchantment in Baking, One Minute Feasts - It's Magic!, Gilderoy Lockhart's Guide to Household Pests (CS3), The Healer's Helpmate (HBP5). Reads Witch Weekly for the recipes (GF28).

Other devices in their house: Kitchen clock with no hours marked, instead the one hand points to "time to make tea, time to feed the chickens, and you're late." (CS3). Weasley grandfather clock with nine golden hands representing Weasley family members. Instead of numbers, the clock has inscriptions of where each family member might be: Home, school, work, traveling, lost, hospital, prison and mortal peril (GF10); golden watch from her brother Fabian, given to Harry on his 17th birthday (DH7); wristwatch (GF5), magical mangle to help with the laundry (DH6).

She has cooked lots of things, including: birthday cakes, fudge, plum cake, mince pies, nut brittle, fruitcake, meat pies, breakfasts of sausages and fried eggs (CS3), dinner of chicken and ham pie, boiled potatoes, salad and strawberry ice cream (GF5), cauldron of stew with bread with rhubarb crumble and custard for dessert (OP5), meatballs (OP7), luncheon of roast chicken and mashed potatoes (OP9), onion soup with bread (HBP5), scrambled eggs, sausages and toast (HBP5), Christmas Eve dinner that included brussel sprouts, carrots, and satsumas (HBP16), apple tarts (DH6).

Molly keeps up a garden that is large and messy, with lots of flowers (including honeysuckle, rhododendrons and roses) and a pond full of frogs (CS3). Vegetables too, including carrots (HBP16), and an orchard (DH7). They also have fat, brown chickens (CS3) as livestock.