NGC 2236:: a moderately metal-poor open cluster of Hyades-like age located beyond the Perseus spiral arm

New CCD photometry in the Washington system C and T, passbands down to T-1 similar to 18.5 mag in the field of the northern open cluster NGC 2236 is presented. T-1 magnitudes and C - T-1 colours for a total of 1162 stars within an area of 13.6 x 13.6 arcmin(2) were measured. These CCD data were supplemented with photoelectric CMT1 T-2 photometry of 13 red giant candidates. The comparison of the cluster (T-1, C - T-1) colour-magnitude diagram with theoretical isochrones computed for the Washington system yields E(C - T-1) = 1.10 +/- 0.10 and T-1 - M-T1, = 13.45 +/- 0.25 for log t = 8.80 (t = 600(-40)(+100) Myr) and Z = 0.008. The derived E(C - T-1) value implies E(B - V) = 0.55 +/- 0.05. NGC2236 is then located at 2.5 +/- 0.5 kpc from the Sun beyond the Perseus spiral arm and at similar to 10.8 kpc from the Galactic centre. A cluster angular diameter of 9.4 arcmin, equivalent to 6.8 pc, was estimated from star counts both within and outside the cluster field. We also derived from the stellar density profile a cluster core radius of r(c) = 1.7 arcmin (1.2 pc) and an annular corona of Delta r(c) = 1.8r(c) (2.2 pc). Five independent Washington abundance indices yield a mean cluster metallicity of [Fe/H] = -0.3 +/- 0.2, which is not only in reasonably good agreement with the one obtained from the isochrone fit, but also compatible with the existence of a radial abundance gradient in the Galactic disc. We examined the properties of a sample of 20 known open clusters aligned along the line-of-sight to NGC 2236. Berkeley 27 appears as the farthest and oldest cluster of the studied sample.