I know Wiki is often not the best source but here is their article about night bombers (it names only 3 types, Wellingtons, Whitley and B29s later.). But seems I was wrong above and Wellington was not meant (at least early) as a night bomber:
Interwar period and World War II
As aircraft capabilities grew, so did their defensive firepower. By the mid-1930s, opinions were changing and the idea of daylight raids of aircraft providing their own self-defense came to the fore. In practice these aircraft proved entirely vulnerable to modern fighter aircraft and were rapidly returned to the night bombing role. However, these aircraft had not been designed for night navigation, and were generally lacking any effectiveness in these missions:
I don't think we realized at the time that our equipment wasn't really up to it. They'd forgotten to design or produce any navigation equipment, so the Wellington bomber, which was intended to be a day bomber, had to operate at night because it was so vulnerable during the day. It had virtually the same equipment that the Tiger Moth had, with one exception—the Wellington had a loop aerial. Here we were flying 500 or 600 miles over enemy territory, trying to locate a target in total blackout, often with cloud below us and a lot of industrial haze. It's not surprising that our bombers were 5, 10 miles away. There was no bomber stream. We were largely on our own, perhaps 10 or 14 aircraft at intervals.
—John Gee, Bomber Command pilot
The USAAF was the only force to press ahead with daylight strategic bombing raids during World War II. This proved as disastrous as the earlier Royal Air Force and Luftwaffe attempts, and had to be called off in late 1943. The arrival of the P-51 Mustang fighter in the "bomber escort" role allowed these missions to start again in 1944, and the fighter was so successful that the Luftwaffe fighter force was largely wiped out by the end of spring. Attrition of the Luftwaffe was so great that the RAF was also able to take to the daylight skies later that year.
The USAAF also applied the same concept with the bombing raids against Japan in June 1944-early 1945 with daylight precision bombing against Japanese industrial facilities using Boeing B-29 Superfortress heavy bombers. However, the results weren't successful because of the frequent jetstream blowing the high explosives off target, navigation problems, anti-aircraft fire, and searchlights, resulting in high losses among the B-29 crewmen. As a result, in February 1945, the USAAF switched to low-level incendiary raids against Japanese cities, most of them took place at night. The most devastating air raid in the war was the firebombing of Tokyo on the night of March 9–10, 1945, which destroyed 16 square miles, killed 100,000 Japanese, and made a million people homeless.
No aircraft used operationally in WWII was "designed" for night bombing; some were adapted for it with additional equipment, while most were simply assigned to night missions. Even the Halifax and Lancaster were intended for daylight operations, but their light defensive armament would have made such missions over Germany suicidal in 1943-44.
There are a number of problems with that Wikipedia article, probably due to a lack of good sources cited.
The 8th AF did not halt daylight precision raids after the Oct 14, 1943 Schweinfurt mission; it simply restricted raids in Germany to the Ruhr region and Bremen, which were within range of P-38s and P-47s. When the 354th FG and its P-51s became operational in Dec 1943, the 8th AF again ranged further into Germany, although raids were few through the end of February because of unusually bad weather.
The 20th and 21st Bomber Commands never halted daylight precision raids over Japan; instead, they interspersed them with night incendiary raids which were much more effective. Daylight precision raids had to continue because the supply of incendiary bombs could not keep up with the pace of their use. From early 1945 until the end of the war, daylight raids were typically carried out from 20,000 to 25,000 feet (just as in Europe), rather than 27-30,000 feet. This improved accuracy and since most of the Japanese fighters available for Home defense didn't perform all that well above 20,000, losses to the unescorted B-29s were acceptable (compared to Europe).